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Objective-C中字符串NSString的常用操作方法总结

时间：2020-02-26 23:38 编辑：来源：阅读：
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摘要：Objective-C中字符串NSString的常用操作方法总结

[b]1.创建字符串[/b] （1）常量字符串

NSString *string = @"i am an iOSDevTip!";

（2）常用创建方法

NSString *string = [[NSString alloc] init];
string = @"i am an iOSDevTip too!";

（3）用initWithString创建字符串

[u]复制代码[/u] 代码如下:

NSString *string = [[NSString alloc] initWithString:@"iOSDevTip is here!"];

[b]2.格式化创建字符串[/b] （1）int格式化字符串

[u]复制代码[/u] 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

[u]复制代码[/u] 代码如下:

NSString *name = @"iOSDevTip";

NSString *personName = [NSString stringWithFormat:@"this person name is %@",name];

[b]3.字符串比较[/b] （1）isEqualToString方法比较

[u]复制代码[/u] 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

[u]复制代码[/u] 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。

[u]复制代码[/u] 代码如下:

typedef NS_ENUM(NSInteger, NSComparisonResult) {NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending};

[b]4.字符串大小写转换[/b] （1）小写转大写

[u]复制代码[/u] 代码如下:

 NSString *string = @"This is an iOSDevTip!";

[string lowercaseString];

（2）大写转小写

[u]复制代码[/u] 代码如下:

NSString *string = @"This is an iOSDevTip!";

[string uppercaseString];

（3）首字母大写

[u]复制代码[/u] 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

[b]5.截取字符串[/b] （1）substringToIndex截取字符串

[u]复制代码[/u] 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

[u]复制代码[/u] 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

[u]复制代码[/u] 代码如下:

NSString *rangeString = [string substringWithRange:NSMakeRange(6, 3)];

截取的rangeString为s a! [b]6.判断字符串是否包含另一个字符串[/b] （1）rangeOfString判断

[u]复制代码[/u] 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

[u]复制代码[/u] 代码如下:

NSString *string = @"I love China";

BOOL isHasI = [string hasPrefix:@"I"];

BOOL isHasChina = [string hasSuffix:@"China"];

[b]7.分割字符串 [/b]

[u]复制代码[/u] 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

[b]8.插入字符串 [/b]

[u]复制代码[/u] 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

[u]复制代码[/u] 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

[b]9.删除字符串 [/b]

[u]复制代码[/u] 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

[b]10.替换字符串 [/b]

[u]复制代码[/u] 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

[b]11.去除字符串首尾的空格和换行符 [/b]

[u]复制代码[/u] 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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