字符串的常见操作

来源：互联网发布：mysql 三目表达式编辑：程序博客网时间：2024/04/29 04:59

/*NSString 常用方法 */

NSString *str0 = @"第一个字符串";

NSString *str1 = [[NSStringalloc]initWithString:str0];

NSLog(@"str1 = %@", str1);

NSString *str2 = [[NSStringalloc]initWithFormat:@"第二个字符串"];

NSLog(@"第%d个字符串 %@", 2, str2);

[str1release];

[str2release];

NSString *name1 = @"宽宽";

NSString *name2 = @"王子洁";

NSString *pari = [[NSStringalloc]initWithFormat:@"%@, %@", name1, name2 ];

for (int i =1; i <= 100; i++) {

@autoreleasepool {

NSString *str3 = [NSStringstringWithFormat:@"第%d个字符串", i];

NSLog(@"%@", str3);

}

// 创建一个新的字符串，可以使用初始化方法和便利构造器。

// 获取字符串长度。

NSLog(@"%lu", [parilength]);

NSLog(@"%lu", [@"正常的字符串" length]);

// 判断字符串的是否以指定字符串开始或结束。

if ([name2 hasPrefix:@"王"]) {

NSLog(@"王子洁");

}

if ([name2 hasSuffix:@"洁"]) {

NSLog(@"恭喜你答对了");

}

// jpg, png, jpeg, gif, bmp

NSString *fileName = @"kuankuan.jpg";

if ([fileName hasSuffix:@".jpg"] || [fileNamehasSuffix:@".png"] || [fileNamehasSuffix:@".jpeg"] || [fileNamehasSuffix:@".gif"] || [fileNamehasSuffix:@".bmp"]) {

NSLog(@"%@是一张图片", fileName);

}else

{

NSLog(@"%@不是一张图片", fileName);

}

// 搜索字符串范围。

NSString *text = @"aBcD_EfGk";

NSRange range = [text rangeOfString:@"王洁"];

NSLog(@"%lu, %lu", range.location, range.length);

if (range.location ==NSNotFound) {

NSLog(@"此人已死,有事烧纸");

}

// 字符串截取(获取子字符串)。

//截取c前面的字符串

NSString *text1 = [text substringToIndex:4];

//截取c后面的字符串

// NSRange range1 = {4, 5};

// NSRange range4 = {0};

// range4.location = 4;

// range4.length = 5;

NSRange range2 = NSMakeRange(4,5);

NSString *text3 = [text substringWithRange:range2];

NSString *text2 = [text substringFromIndex:9];

NSLog(@"%@%@%@", text1, text3, text2);

// 拼接字符串。

NSString *Love = [NSStringstringWithFormat:@"常宽"];

NSLog(@"%@", [[LovestringByAppendingString:@"回家生猴子"]stringByAppendingString:@"le"]);

NSLog(@"%@", [LovestringByAppendingFormat:@"回家生猴子"]);

NSLog(@"%@", [LovestringByPaddingToLength:7withString:@"回家生猴子"startingAtIndex:0]);

// 替换字符串。

NSString *e3 = [NSStringstringWithFormat:@"2B青年"];

NSString *e4 = @"宽宽";

NSLog(@"%@", [e3stringByReplacingOccurrencesOfString:@"2B"withString:e4]);

NSRange range3 = {0,2};

NSString *e5 = [e3stringByReplacingCharactersInRange:range3 withString:@"小宽宽"];

NSLog(@"%@", e5);

// 字符串比较。

NSLog(@"%ld", [@"A"compare:@"A"]);// 0代表字符串相等

NSLog(@"%ld", [@"B"compare:@"A"]);// 1代表降序排列

NSLog(@"%ld", [@"A"compare:@"B"]);// -1代表升序排列

NSLog(@"%ld", [@"BA"compare:@"BB"]);

NSLog(@"%ld", [@"A"compare:@"C"]);

NSLog(@"~~~~%ld", [@"子杰"compare:@"宽宽"]);

// 字符串和数值类型转换。

NSString *pi = @"3.1415926";

double p = [pi doubleValue];

NSLog(@"p = %.7f", p);

int a = 5;

NSString *aa = [NSStringstringWithFormat:@"%d", a];

NSLog(@"aa = %@", aa);

//大小写转换操作。

NSString *str5 = @"asdasfsf";

NSString *str6 = @"SDFJS";

//全部转为大写

NSLog(@"%@",[str5uppercaseString]);

//全部转为小写

NSLog(@"%@",[str6lowercaseString]);

NSString *ee = @"aBcD_EfGk";

NSRange rang = [ee rangeOfString:@"EfGk"];

if (rang.location !=NSNotFound ) {

NSString *bb = [[textstringByReplacingOccurrencesOfString:@"EfGk"withString:@"WXYZ"]lowercaseString];

NSLog(@"%@", bb);

}

NSString *picName = @"xiao.png";

if ([picName hasSuffix:@".png"]) {

NSString *pic = [picNamestringByReplacingOccurrencesOfString:@".png"withString:@".jpg"];

NSLog(@"%@", pic);

}

/* NSMutableString 常用方法*/

// 1.创建一个新的字符串

NSMutableString *mStr1 = [NSMutableStringstringWithFormat:@"可变字符串"];

// 2.拼接字符串

[mStr1appendString:@"可以变长"];

NSLog(@"%@", mStr1);

// mStr1 = [NSMutableString stringWithString:[mStr1 stringByAppendingString:@"很多"]];//把一个不可变的字符串对象通过用创建对象的方式转变成一个可变的字符串

NSLog(@"%@", mStr1);

// 3.插入字符

[mStr1insertString:@"的很"atIndex:8];

NSLog(@"%@", mStr1);

// 4.删除字符

[mStr1 deleteCharactersInRange:NSMakeRange(5,2)];

NSLog(@"%@", mStr1);

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