iOS 工作之余小总结（四）--（1）可变与不可变字符串方法大全

对于集合来说，就像我们手里的工具一样，练习的越熟练，对于工作 上的发开和思维上的逻辑就越有敏捷。话不多说，直接上方法和代码：

1不可变字符串NSString（对象在代码区）
//1.创建
NSString *fyStr1 = [[NSString alloc] init];
NSString *fyStr2 = @”Hello world!”;
NSString *fyStr3 = [NSString stringWithFormat:@”%@ world!”, @”Hello”];//格式化创建
NSString *fyStr4 = [NSString stringWithString:fyStr3];

//2.截取
NSString *fyStr5 = @”www.fyFY.cn”;
NSString *fyStr6 = [fyStr5 substringToIndex:3];//截取头
NSString *fyStr7 = [fyStr5 substringFromIndex:9];//截取尾
NSString *fyStr8 = [fyStr5 substringWithRange:NSMakeRange(4, 4)];//截取中段

//3.拼接
NSString *fyStr10 = @”Hello “;
NSString *fyStr11 = @”world!”;
NSString *fyStr12 = [NSString stringWithFormat:@”%@%@”, fyStr10, fyStr11];//工厂方法
NSString *fyStr13 = [[NSString alloc] initWithFormat:@”%@%@”, fyStr10, fyStr11];//初始
NSString *fyStr14 = [fyStr10 stringByAppendingString:fyStr11];//追加拼接
NSString *fyStr15 = [fyStr10 stringByAppendingFormat:@”%@”, fyStr11];//格式化

//4.替换
NSString *fyStr16 = @”www.fyfyfy.com.cn”;
NSString *fyStr17 = [fyStr16 stringByReplacingCharactersInRange:NSMakeRange(4, 10) withString:@”FYFY”];

//5.判断字符串中是否包含某个子串
NSString *fyStr18 = @”feng yong”;
NSString *fyStr19 = @”feng”;
if ([fyStr18 rangeOfString:fyStr19].location != NSNotFound) {
//TODO
NSLog(@”sakgfkashoh”);
}

//6.是否包含前缀和后缀
NSString *fyStr20 = @”www.fyfyfy.com”;
if ([fyStr20 hasPrefix:@”www”]) {
//TODO
} //判断前缀
NSString *fyStr21 = @”www.fyfyfy.com”;
if ([fyStr21 hasSuffix:@”com”]) {
//TODO
} //判断后缀

//7.获取长度
NSString *fyStr22 = @”fyabc”;
NSUInteger length = str.length;

2.可变字符串NSMutableString（对象在堆区）
首先说，可变字符串是不可变字符串的子类，所以可变字符串可以用不可变里的方法。一下是派生的方法：

//1.创建
NSMutableString *fyStr1 = [[NSMutableString alloc] init];//空串，有意义
NSMutableString *fyStr2 = [NSMutableString stringWithCapacity:100];//预估值
NSMutableString *fyStr3 = @”abc”;//退化成不可变字符串。
NSMutableString *fyStr4 = [NSMutableString stringWithString:@”string”];//初始化
NSMutableString *fyStr5 = [NSMutableString stringWithFormat:@”age:%d”, 10];//格式化初始化

//2添加
NSMutableString *fyStr6 = [NSMutableString stringWithCapacity:20];
[fyStr6 appendString:@”fyfyfy”];//向字符串中追加字符串
[fyStr6 insertString:@”haha” atIndex:0];//向指定的位置插入指定的字符串

//3替换
NSMutableString *fyStr8 = [NSMutableString stringWithString:@”i am a worker”];

//4删除
NSMutableString *fyStr7 = [NSMutableString stringWithString:@”my name is feng yong”];
[fyStr7 deleteCharactersInRange:NSMakeRange(0, 2)];