(void)string{

NSMutableString *strBase = [[NSMutableString alloc]initWithString:@"你是一串字符串呀呀呀！"];
NSLog(@"strBase====%@",strBase);
NSString *str0 = [strBase stringByReplacingOccurrencesOfString:@"呀" withString:@""];//去掉字符串内的“呀”字，适用于去掉空格
NSLog(@"str0=======%@",str0);
NSString *str1 = [strBase substringWithRange:NSMakeRange(4, 3)];//从4位截取,截取长度为3
NSLog(@"str1=======%@",str1);
NSString *str2 = [strBase substringToIndex:7];//截取7位
NSLog(@"str2=======%@",str2);
NSString *str3 = [strBase substringFromIndex:7];//从第7位开始截取
NSLog(@"str3=======%@",str3);
NSArray *arrStr = [strBase componentsSeparatedByString:@"串"];//分割数组
for (int i = 0; i < arrStr.count; i++){
    NSLog(@"arrStr[%d]=======%@",i,arrStr[i]);
}
NSString *str4 = [strBase stringByAppendingString:@"跟屁虫"];//拼接字符串
NSLog(@"str4=======%@",str4);

[strBase replaceCharactersInRange:NSMakeRange(0, 1) withString:@"我"];//替换:指定位置替换
NSLog(@"strBase====%@",strBase);
[strBase insertString:@"，就是我" atIndex:1];//插入字符串
NSLog(@"strBase=======%@",strBase);
[strBase deleteCharactersInRange:NSMakeRange(0, 2)];//删除字符串
NSLog(@"strBase=======%@",strBase);

}