NSString （API+常用实例）

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//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;

//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;

}

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