Foudation框架之字符串

一 字符串

二 可变字符串的初始化方法

对象方法的初始化

//init是对象方法

//将不可变字符串转换为可变字符串

NSMutableString *str2=[[NSMutableString alloc] initWithString:str1];

NSLog(@"%ld",str2.length);

//        [str2 insertString:@"lll" atIndex:3];

//        NSLog(@"%@",str2);

//拼接字符串，插入最后前，字符串长度自然多加后面字符串长度 与C语言不同长度数组越界 拼接之前 atIndex后面就是 0

[str2 insertString:@"and lisi" atIndex:str2.length];

NSLog(@"%@",str2);

//在后面拼接

[str2 appendString:@"and lisi"];

//从0开始删除3个字符

[str2 deleteCharactersInRange:NSMakeRange(6, 5)];

//替换字符串替换范围内的字符串

[str2 replaceCharactersInRange:NSMakeRange(6, 5) withString:@"wang"];

//替换所有的字符的字符串

[str2 replaceOccurrencesOfString:@"a" withString:@"p" options:NSCaseInsensitiveSearch range:NSMakeRange(0, str2.length)];

//将C语言字符串转为可变字符串

char *name="zhangsan";

NSMutableString *str3=[[NSMutableString alloc] initWithUTF8String:name];

NSLog(@"%ld",str3.length);

//通过格式化来初始化可变字符串

NSMutableString *str4=[[NSMutableString alloc] initWithFormat:@"hell%d",123];

NSLog(@"%ld",str4.length);

//通过字符串的长度来初始化字符串  0

NSMutableString *str5=[[NSMutableString alloc] initWithCapacity:10];

//直接初始化  0

NSMutableString *str6=[[NSMutableString alloc] init];

[str6 insertString:@"lisi" atIndex:0];

//stringwith是类方法

NSMutableString *str7=[NSMutableString stringWithUTF8String:name];

NSMutableString *str8=[NSMutableString stringWithFormat:@"hell%d",123];

NSMutableString *str9=[NSMutableString string];

NSMutableString *str10=[NSMutableString stringWithString:@"lisi"];

类方法的初始化

三