NSString （API+常用实例）

iOS 字符串常用方法

-(void)teset{
//初始化

NSString* str = [NSString stringWithFormat:@"asdfsdfvvvvvvvas"];
NSString* str2 = @"110A";
NSString* str3 = @"110a";



//字符串长度
//@lengh （readonly）
NSLog(@"字符串长度:%ld",(long)str.length);



//获取字符串某位
unichar c = [str characterAtIndex:1];



//根据下标和长度截取字符串
NSRange rang = {6,8};
NSString* str4 = [str substringWithRange:rang];
NSLog(@"截取字符串:%@",str4);



//从指定下标截取到最后
NSString* str5 = [str substringFromIndex:3];
//从下标[0]到指定下标[3],但不包括[3]
NSString* str6 = [str substringToIndex:3];
NSLog(@"%@ %@",str5,str6);



//强转
NSInteger i = [str4 intValue];
NSLog(@"%d",i+1);
double f = [str4 floatValue];
long long l = [str4 longLongValue];



//转大写
NSString* bigStr = [str3 uppercaseString];
NSLog(@"%@",bigStr);
//转小写
NSString* smallStr = [str2 lowercaseString];
NSLog(@"%@",smallStr);
//首字母大写
NSString *firstPer = [str capitalizedString];




//切割字符串
NSArray *ary = [str componentsSeparatedByString:@","];



//拼接字符串
//stringByAppendingString
NSString *appenStr = [str stringByAppendingString:@"aaa"];
//appendString
NSMutableString *mutableStr = [NSMutableString stringWithString:@"fsfsfsdff"];
[mutableStr appendString:@"拼接的dfdsfdf"];




//前后缀判断
//判断前缀
if ([str hasPrefix:@"44"])
{
    NSLog(@"YES");
}
//判断后缀
if ([str hasSuffix:@"0302"])
{
    NSLog(@"YES");
}
//- (NSString *)commonPrefixWithString:(NSString *)str options:(NSStringCompareOptions)mask;
//前缀忽略大小写，最终成功返回前缀"A"，不成功返回 "空字符串"
NSString *b5 = [@"A A" commonPrefixWithString:@"b" options:NSCaseInsensitiveSearch];



//两字符串是否相等，完全匹配
if ([str isEqualToString:str2])
{
    NSLog(@"一样,");
    
}




//忽略大小写匹配两字符串
NSComparisonResult b = [str2 caseInsensitiveCompare:str3];
if (b==0) {
    NSLog(@"忽略大小写==0就是相等，-1不等");
}
b = [str2 compare:@"022"];





//- (NSComparisonResult)compare:(NSString *)string
//字符串高级匹配
/*
 typedef NS_OPTIONS(NSUInteger, NSStringCompareOptions) {
 NSCaseInsensitiveSearch = 1,   //忽略大小写
 NSLiteralSearch = 2,   //区分大小写
 NSBackwardsSearch = 4,   //从源字符串的结尾搜索
 NSAnchoredSearch = 8,   //搜索限制范围的字符串
 NSNumericSearch = 64,   //按照字符串里的数字对比，必须相同格式如 1.1.1>1.1.0
 NSDiacriticInsensitiveSearch   //忽略 "-"符号的比较
 NSWidthInsensitiveSearch       //忽略字符串的长度，比较出结果
 NSForcedOrderingSearch         //忽略不区分大小写比较的选项，并强制返回 NSOrderedAscending或者 NSOrderedDescending
 NSRegularExpressionSearch      //只能应用于 rangeOfString:..., stringByReplacingOccurrencesOfString:...和 replaceOccurrencesOfString:... 方法。使用通用兼容的比较方法，如果设置此项，可以去掉 NSCaseInsensitiveSearch 和 NSAnchoredSearch
 */

/*
 *  typedef NS_ENUM(NSInteger, NSComparisonResult)
 {NSOrderedAscending = -1L  升序
 NSOrderedSame,             相同
 NSOrderedDescending};      降序
 */
NSString *numA = @"2.1.16";
NSString *numB = @"2.1.11";

NSComparisonResult bb = [numA compare:numB options:NSNumericSearch];
if (bb == NSOrderedDescending)
{
    NSLog(@"BigOne:%@",numA);
}else
{
    NSLog(@"smallOne:%@",numB);
}



//字符串比较 @"你4402042,0040302"
NSComparisonResult b2 = [str localizedCompare:@"2042"];  //1 降序 -1升序  0相同



//忽略大小写匹配
NSComparisonResult b3 = [@"aa bb" localizedCaseInsensitiveCompare:@"AA BB"];  //1降序 -1升序  0相同



//- (NSComparisonResult)localizedStandardCompare:(NSString *)string
NSComparisonResult b4 = [@"A A" localizedStandardCompare:@"A A"];  //1 降序 -1升序  0相同



//- (BOOL)containsString:(NSString *)str NS_AVAILABLE(10_10, 8_0);
//字符串内容中是否包含指定项  ios8以上方法
BOOL b6 = [str containsString:@"0040"];
//- (BOOL)localizedCaseInsensitiveContainsString:(NSString *)str NS_AVAILABLE(10_10, 8_0);
//忽略大小写判断包含字符串    ios8以上方法
BOOL b7 = [@"adfdsffff" localizedCaseInsensitiveContainsString:@"FFFF"];



//- (NSRange)rangeOfString:(NSString *)searchString;2.4
//判断一个字符串是否包含另一个字符串:
NSString *str11=@"中华人民共和国";
NSString *str22=@"中华";
NSString*str33= [str11 rangeOfString:str22].length !=0?@"found it":@"not found";
NSLog(@"result:%@",str33);

//根据所搜索字符串，返回所在位置，通常根据 range.lenght长度判断是否包含
/* 对应可以设置 options：是否忽略大小写、数字对比....   range：限定范围处理
 - (NSRange)rangeOfString:(NSString *)searchString options:(NSStringCompareOptions)mask;
 - (NSRange)rangeOfString:(NSString *)searchString options:(NSStringCompareOptions)mask range:(NSRange)searchRange;
 - (NSRange)rangeOfString:(NSString *)searchString options:(NSStringCompareOptions)mask range:(NSRange)searchRange locale:(nullable NSLocale *)locale
 */
NSRange subRange = {4,4};
NSRange range4 = [@"adfdsffff" rangeOfString:@"FFF" options:NSCaseInsensitiveSearch range:subRange];

}
//判断是否纯数字
//第三种方式则是使用NSString的trimming方法

• (BOOL)isPureNumandCharacters:(NSString *)string
  {
  string = [string stringByTrimmingCharactersInSet:[NSCharacterSet decimalDigitCharacterSet]];
  if(string.length > 0)
  {
  return NO;
  }
  return YES;
  }