NSString

NSString 不可变字符串

字面量

<code class="hljs rust has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">NSString *<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"呵呵"</span>;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

通过alloc和init创建的一个空字符串

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str = [[<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> alloc] init];</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

初始化一个字符串

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str = [[<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> alloc] initWithString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"刘"</span>];<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, str);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

系统提供的便利构造器的方法

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> stringWithString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"你好"</span>];</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

用便利构造器和初始化方法创建字符串对象可以,也能正常使用,但是系统还是更倾向于用字面量的方式来完成对象的创建

length字符串的长度

<code class="hljs rust has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">NSString *<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"呵呵"</span>;NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%ld"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span>.length);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

字符串的截取

<code class="hljs rust has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">NSString *<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"nihao,wodemingzijiaolishanshan"</span>;NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> substringFromIndex:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">6</span>]);NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> substringToIndex:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">5</span>]);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

NSRange 是一个结构体,提供了两个成员变量,一个是location起始位置,还有一个是长度

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"nihao,wodemingzijiaolishanshan"</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSRange</span>  range = {<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">7</span>};<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, [str substringWithRange:range]);<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, [str substringWithRange:NSMakeRange(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">7</span>)]);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

判断两个字符串内容是否相同, 是个BOOL值,返回值是0和1

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str1 = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"hello world"</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str2 = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"hello world"</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%d"</span>, [str1 isEqualToString:str2]);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

hasPrefix:是否有前缀 hasSuffix:是否有后缀

<code class="hljs rust has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">NSString *<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"lishanshan"</span>;NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%d"</span>, [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> hasPrefix:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"li"</span>]);NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%d"</span>, [<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> hasSuffix:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"an"</span>]);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

把字符变成基本数据类型, 遇到不是基本类型的会直接打断

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> * strNum = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"123s45"</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSInteger</span> num = [strNum integerValue];<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%ld"</span>, num);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

stringWithFormat: 方法可以把任意类型转换成字符串类型,可以进行拼接

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">CGFloat</span> g = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3.14</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSInteger</span> a = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> stringWithFormat:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%ld, %g, %@"</span>, a, g, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"李珊珊"</span>];<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, str);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

uppercaseString:所有的字符都大写 lowercaseString:所有的字符都小写 capitalizedString:首字母大写, 其余都小写

<code class="hljs rust has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">NSString *<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"li sHan shan"</span>;NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span>.uppercaseString);NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span>.lowercaseString);NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span>.capitalizedString);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

对应只有三个结果, 一个是ASC 升序, 其结果是:1,一个是same 相同,结果是:0,DESC 降序 结果是:1

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"buhao"</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *newStr = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"buhao"</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%ld"</span>,[str compare:newStr]);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

字符串的拼接

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"lishanshan"</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str1 = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"shangshuai"</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *newStr = [str stringByAppendingString:str1];<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, newStr);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

替换 并没有改变原字符串, 需要新建一个字符串用来接受

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *str = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"商帅没事喜欢飞"</span>;<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSString</span> *strNew = [str stringByReplacingOccurrencesOfString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"刘"</span> withString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"李"</span>];<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>,strNew);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

NSMutableString: 可变字符串, 他是NSString的子类

使用字面量的方式创建的是不可变的字符串,只能拿不可变的指针来接受

<code class="hljs rust has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">NSMutableString * <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> = @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"杨林"</span>;    是错误的.</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

可变字符串的定义 
自定义初始化

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSMutableString</span> *str = [[<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSMutableString</span> alloc] initWithString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"腾飞"</span>];<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, str);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

便利构造器

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSMutableString</span> *str1 = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSMutableString</span> stringWithString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"刘山"</span>];<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, str1);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

插入 也可用来拼接

<code class="hljs rust has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">NSMutableString *<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> = [NSMutableString stringWithString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"nihao, wo jiao shangshuai"</span>];[<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> insertString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"刘山"</span> atIndex:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">5</span>];NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span>);[<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> replaceCharactersInRange:NSMakeRange(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) withString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"大傻子"</span>];NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span>);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

拼接

<code class="hljs rust has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">NSMutableString *<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> = [[NSMutableString alloc] init];[<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> setString:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"不开心"</span>];NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span>);[<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span> appendFormat:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"你们都太脏了"</span>];NSLog(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">str</span>);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

可变字符串在方法上一般都是没有返回值得,但是对自身的内容进行修改,在访问的时候字符串已经发生了变化,但是不可改变字符串会产生一个新的字符串,一般方法会返回NSString *,

数组

0C里的数组存放的一定是对象

字面量

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSArray</span> *arr = @[@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"2"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"3"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"4"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"5"</span>];</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

用便利构造器的方式创建一个空数组

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSArray</span> *arr = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSArray</span> array];</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

用便利构造器的方式创建一个数组

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSArray</span> *arr = [<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSArray</span> arrayWithObjects:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"2"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"3"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"4"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"5"</span>, <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">nil</span>];<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSInteger</span> i = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>; i < arr<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.count</span>; i++) {        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, arr[i]);}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

初始化定义一个数组

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSArray</span> *arr = [[<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSArray</span> alloc] initWithObjects:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"2"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"3"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"4"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"5"</span>, <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">nil</span>];</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

count: 数组里的元素个数

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSArray</span> *arr = @[@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"2"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"3"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"4"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"5"</span>];<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%ld"</span>, arr<span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">.count</span>);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

也是通过下标进行取值, 返回一个对象

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, [arr objectAtIndex:<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>]);<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%@"</span>, arr[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>]);     <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 数组下标是从零开始的</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

containsObject 判断数组中是否包含 BOOL类型

<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSArray</span> *arr = @[@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"2"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"3"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"4"</span>, @<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"5"</span>];<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSLog</span>(@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"%d"</span>,[arr containsObject:@<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"4"</span>]);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>