iOS：NSString有关使用

1、字符串的编码、解码

//编码-(NSString *) encodingString:(NSString *)string{//iOS9之前//NSString *str = [string stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];//iOS9之后NSString *str = [string stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];NSLog(@\"编码 -- %@\",str);return str;}//解码-(NSString *)decodeString:(NSString *)string{//iOS9之前//NSString *str = [string stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];//iOS9之后NSString *str = [string stringByRemovingPercentEncoding];NSLog(@\"解码 -- %@\",str);return str;}

2、大小写切换

//改变大小写-(NSString *)changeStringToUpperOrLower:(NSString *)components type:(NSInteger)type{NSString *str;if (type == 0) {str = [components uppercaseString];//转成大写}else if (type == 1){str = [components lowercaseString];//转成小写}else{str = [components capitalizedString];//首字母大写 其余小写}NSLog(@\"StringToUpperOrLower--%@\",str);return str;}

3、验证字符串 – hasPrefix:0、hasSuffix:1

//验证字符串 - hasPrefix:0、hasSuffix:1-(BOOL)verifyString:(NSString *)string hasString:(NSString *)str preOrSuf:(NSInteger)preOrSuf{BOOL ishas;if (preOrSuf == 0) {//头部ishas = [string hasPrefix:str];}else {//尾部ishas = [string hasSuffix:str];}NSLog(@\"验证字符串  %ld -- %d\",preOrSuf,ishas);return ishas;}

4、替换字符串

//替换字符串 --(NSString *)replacingComponents:(NSString *)components oldString:(NSString *)old newString:(NSString *)new{NSString *str = [components stringByReplacingOccurrencesOfString:old withString:new];NSLog(@\"替换字符串 -- %@\",str);return str;}

5、查找字符串

//查找字符串 - 返回range-(NSRange)rangeComponents:(NSString *)components withString:(NSString *)string{NSRange range = [components rangeOfString:string];NSLog(@\"range -- %@\",NSStringFromRange(range));return range;}

6、截取字符串

//截取字符串 - 返回字符串-(NSString *)subStringWith:(NSString *) string withIndex:(NSInteger)index withLength:(NSInteger)length{NSString *str;if (index>0&&length>0) {//从下标index字符串开始截取length长度的字符串str = [string substringWithRange:NSMakeRange(index, length)];}else if (index==0&&length>0){//从首字符开始截取length个字符str = [string substringToIndex:length];}else if(index>0&&length==0){//从第index位开始截取,至字符串最后str = [string substringFromIndex:index];}NSLog(@\"subString -- %@\",str);return str;}

7、分隔字符串

//分隔字符串 - 返回数组-(NSArray *)separatedWithComponents:(NSString *)components byString:(NSString *)string{NSArray *array = [components componentsSeparatedByString:string];NSLog(@\"array -- %@\",array);return array;}

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