Objective-C中字符串NSString的常用操作方法总结
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2023-12-11 23:04:34
1.创建字符串
（1）常量字符串
复制代码 代码如下:
nsstring *string = @"i am an iosdevtip!";
（2）常用创建方法...
1.创建字符串
（1）常量字符串
复制代码 代码如下:
nsstring *string = @"i am an iosdevtip!";
（2）常用创建方法
复制代码 代码如下:
nsstring *string = [[nsstring alloc] init];
string = @"i am an iosdevtip too!";
（3）用initwithstring创建字符串
复制代码 代码如下:
nsstring *string = [[nsstring alloc] initwithstring:@"iosdevtip is here!"];
2.格式化创建字符串
（1）int格式化字符串
复制代码 代码如下:
int age = 20;
nsstring *personage = [nsstring stringwithformat:@"this person age is %d",age];
既然int格式化字符串，那么float、double等，也可以格式化字符串。
（2）nsstring格式化字符串
复制代码 代码如下:
nsstring *name = @"iosdevtip";
nsstring *personname = [nsstring stringwithformat:@"this person name is %@",name];
3.字符串比较
（1）isequaltostring方法比较
复制代码 代码如下:
nsstring *stingone = @"this is an iosdevtip!";
nsstring *stringtwo = @"this is an iosdevtip!";
bool result = [stingone isequaltostring:stringtwo];
（2）compare方法比较
复制代码 代码如下:
bool result = [stingone compare:stringtwo] == nsorderedsame;
compare:方法返回值类型为nscomparisonresult。而nscomparisonresult有下面几个枚举值。
复制代码 代码如下:
typedef ns_enum(nsinteger, nscomparisonresult) {nsorderedascending = -1l, nsorderedsame, nsordereddescending};
4.字符串大小写转换
（1）小写转大写
复制代码 代码如下:
nsstring *string = @"this is an iosdevtip!";
[string lowercasestring];
（2）大写转小写
复制代码 代码如下:
nsstring *string = @"this is an iosdevtip!";
[string uppercasestring];
（3）首字母大写
复制代码 代码如下:
nsstring *string = @"ligang";
nslog(@"string: %@",[string capitalizedstring]);
打印：
2015-07-16 23:06:11.652 iosstrongdemo[10279:3062010] string: ligang
5.截取字符串
（1）substringtoindex截取字符串
复制代码 代码如下:
nsstring *string = @"this is a operation string!";
nsstring *subtostring = [string substringtoindex:6];
（2）截取的subtostring为this i
substringfromindex截取字符串
复制代码 代码如下:
nsstring *subfromstring = [string substringfromindex:6];
（3）截取的subfromstring为s a operation string!
substringwithrange截取字符串
复制代码 代码如下:
nsstring *rangestring = [string substringwithrange:nsmakerange(6, 3)];
截取的rangestring为s a!
6.判断字符串是否包含另一个字符串
（1）rangeofstring判断
复制代码 代码如下:
nsstring *string1 = @"this is a iosdevtip";
nsstring *string2 = @"iosdevtip";
nsrange range = [string1 rangeofstring:string2];
nsinteger location = range.location;
nsinteger leight = range.length;
nsstring *logstring = [[nsstring alloc] initwithstring:[nsstring stringwithformat:@"location:%ld,leight:%ld",location,leight]];
nslog(@"logstring:%@",logstring);
打印出来：
iosstrongdemo[8837:2221170] logstring:location:10,leight:9
（2）判断是否包含前后缀
复制代码 代码如下:
nsstring *string = @"i love china";
bool ishasi = [string hasprefix:@"i"];
bool ishaschina = [string hassuffix:@"china"];
7.分割字符串
复制代码 代码如下:
nsstring *string = @"this is a iosdevtip";
nsarray *array = [string componentsseparatedbystring:@"a"];
nsstring *string1 = [array objectatindex:0];
nsstring *string2 = [array objectatindex:1];
nslog(@"string1:%@ string2:%@",string1,string2);
打印：
2015-07-16 22:40:39.559 iosstrongdemo[10165:3055448] string1:this is string2: iosdevtip
8.插入字符串
复制代码 代码如下:
nsmutablestring *string = [[nsmutablestring alloc] initwithstring:@"i china"];
[string insertstring:@"love " atindex:2];
nslog(@"string: %@",string);
打印：
2015-07-16 22:44:10.706 iosstrongdemo[10206:3057014] string: i love china
（1）追加字符串
复制代码 代码如下:
nsmutablestring *string = [[nsmutablestring alloc] initwithstring:@"i love "];
[string appendstring:@"china"];
nslog(@"string:%@",string);
打印：
2015-07-16 22:42:32.305 iosstrongdemo[10189:3056410] string:i love china
9.删除字符串
复制代码 代码如下:
nsmutablestring *string = [[nsmutablestring alloc] initwithstring:@"i love china"];
[string deletecharactersinrange:nsmakerange(2, 4)];
nslog(@"string1: %@",string);
打印：
2015-07-16 22:46:58.437 iosstrongdemo[10219:3057749] string1: i china
10.替换字符串
复制代码 代码如下:
nsstring *string = @"i love china";
nsstring *replacestring = [string stringbyreplacingoccurrencesofstring:@"love" withstring:@"like"];
nslog(@"replacestring: %@",replacestring);
打印：
2015-07-16 22:56:07.405 iosstrongdemo[10236:3059503] replacestring: i like china
11.去除字符串首尾的空格和换行符
复制代码 代码如下:
nsstring *string = @" i love china ";
nsstring *text = [string stringbytrimmingcharactersinset:[nscharacterset whitespaceandnewlinecharacterset]];
nslog(@"text:%@",text);
打印：
2015-07-16 23:00:47.845 iosstrongdemo[10265:3061013] text:i love china
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