Objective-C中使用NSString類操作字符串的方法小結(jié)

2020-07-26 03:29:26

字體：大中小

供稿：網(wǎng)友

一、字符串切割
1、帶節(jié)點(diǎn)的字符串，如@"<p>討厭的節(jié)點(diǎn)<br/></p>"我們只想要中間的中文

處理方法：

復(fù)制代碼代碼如下:

NSString *string1 = @"<p>討厭的節(jié)點(diǎn)<br/></p>";
 
/*此處將不想要的字符全部放進(jìn)characterSet1中，不需另外加逗號(hào)或空格之類的，除非字符串中有你想要去除的空格，此處< p /等都是單獨(dú)存在，不作為整個(gè)字符*/
 
NSCharacterSet *characterSet1 = [NSCharacterSet characterSetWithCharactersInString:@"<p/brh>"];
 
// 將string1按characterSet1中的元素分割成數(shù)組
 
NSArray *array1 = [string1 componentsSeparatedByCharactersInSet:characterSet1];
 
NSLog(@"array = %@",array1);
 
for(NSString *string1 in array1)
{
    if ([string1 length]>0) {
         
        // 此處string即為中文字符串
 
        NSLog(@"string = %@",string1);
    }
}

打印結(jié)果：

2016-01-17 10:55:34.017 string[17634:303] array = ( "", "", "", "/U8ba8/U538c/U7684/U8282/U70b9", "", "", "", "", "", "", "", "", "")2016-01-17 10:55:34.049 string[17634:303] string = 討厭的節(jié)點(diǎn)

2、帶空格的字符串，如

@"hello world"去掉空格

復(fù)制代碼代碼如下:

NSString *string2 = @"hello world";
 
/*處理空格*/
 
NSCharacterSet *characterSet2 = [NSCharacterSet whitespaceCharacterSet];
 
// 將string1按characterSet1中的元素分割成數(shù)組
NSArray *array2 = [string2 componentsSeparatedByCharactersInSet:characterSet2];
 
NSLog(@"/narray = %@",array2);
 
// 用來(lái)存放處理后的字符串
NSMutableString *newString1 = [NSMutableString string];
 
for(NSString *string in array1)
{
    [newString1 appendString:string];
}
NSLog(@"newString = %@", newString1);

打印結(jié)果：

2016-01-17 11:02:49.656 string[17889:303] array = ( hello, world)2016-01-17 11:02:49.657 string[17889:303] newString = helloworld

PS：處理字母等其他元素只需將NSCharacterSet的值改變即可。

復(fù)制代碼代碼如下:

+ (id)controlCharacterSet;
 
+ (id)whitespaceCharacterSet;
 
+ (id)whitespaceAndNewlineCharacterSet;
 
+ (id)decimalDigitCharacterSet;
 
+ (id)letterCharacterSet;
 
+ (id)lowercaseLetterCharacterSet;
 
+ (id)uppercaseLetterCharacterSet;
 
+ (id)nonBaseCharacterSet;
 
+ (id)alphanumericCharacterSet;
 
+ (id)decomposableCharacterSet;
 
+ (id)illegalCharacterSet;
 
+ (id)punctuationCharacterSet;
 
+ (id)capitalizedLetterCharacterSet;
 
+ (id)symbolCharacterSet;
 
+ (id)newlineCharacterSet NS_AVAILABLE(10_5, 2_0);
 
+ (id)characterSetWithRange:(NSRange)aRange;
 
+ (id)characterSetWithCharactersInString:(NSString *)aString;
 
+ (id)characterSetWithBitmapRepresentation:(NSData *)data;
 
+ (id)characterSetWithContentsOfFile:(NSString *)fName;

二、用字符將NSArray中的元素拼接起來(lái)

復(fù)制代碼代碼如下:

NSArray *array = [NSArray arrayWithObjects:@"hello",@"world",nil];
 
//如要用,:等字符串拼接，只需將下面的@" "空格換成@","或@":"即可
NSString *string = [array componentsJoinedByString:@" "];
 
NSLog(@"string = %@",string);

打印結(jié)果：

hello world

三、截取子串：

這里以獲取時(shí)間為例，利用NSDate獲取到當(dāng)前時(shí)間時(shí)，有時(shí)候只需要日期或者只需要時(shí)間

1、從字符串開(kāi)頭截取到指定的位置，如

復(fù)制代碼代碼如下:

//獲取到當(dāng)前日期時(shí)間    
NSDate *date = [NSDate date];
         
//定義日期格式,此處不重點(diǎn)討論NSDate，故不詳細(xì)說(shuō)明，在后面會(huì)詳細(xì)討論       
NSDateFormatter *dateformatter = [[NSDateFormatter alloc] init];
         
//設(shè)置日期格式        
[dateformatter setDateFormat:@"YYYY-MM-dd HH:mm"];
         
//將日期轉(zhuǎn)換成NSString類型      
NSString *string = [dateformatter stringFromDate:date];
NSLog(@"/ncurrent = %@",string);
                
//截取日期substringToIndex 
NSString *currentDate = [string substringToIndex:10];
                 
NSLog(@"/ncurrentDate = %@",currentDate);

打印結(jié)果：

current = 2016-01-1711:12currentDate = 2016-01-17

2、抽取中間子串-substringWithRange

復(fù)制代碼代碼如下:

//截取月日
NSString *currentMonthAndDate = [string substringWithRange:[NSMakeRange(5, 5)]];
         
NSLog(@"currentMonthAndDate = %@",currentMonthAndDate);

打印結(jié)果：

currentMonthAndDate = 06-27

3、從某一位置開(kāi)始截取- substringFromIndex

復(fù)制代碼代碼如下:

//截取時(shí)間substringFromIndex
NSString *currentTime = [string substringFromIndex:11];
         
NSLog(@"/ncurrentTime = %@",currentTime);/

打印結(jié)果：

currentTime = 11:25

四、比較字符串

復(fù)制代碼代碼如下:

NSString *first = @"string";
NSString *second = @"String";

1、判斷兩個(gè)字符串是否相同-isEqualToString方法

復(fù)制代碼代碼如下:

BOOL isEqual = [first isEqualToString:second];
 
NSLog(@"first is Equal to second:%@",isEqual);

打印結(jié)果：

first is Equal to second:0

2、compare方法比較字符串三個(gè)值

復(fù)制代碼代碼如下:

NSOrderedSame//是否相同
NSOrderedAscending//升序，按字母順序比較，大于為真
NSOrderedDescending//降序，按字母順序比較，小于為真

BOOL result = [first compare:sencond] == NSOrderedSame;
NSLog(@"result:%d",result);

打印結(jié)果：

result:0

復(fù)制代碼代碼如下:

BOOL result = [first compare:second] == NSOrderedAscending;
NSLog(@"result:%d",result);

打印結(jié)果：

result:0

復(fù)制代碼代碼如下:

BOOL result = [first compare:second] == NSOrderedDecending; NSLog(@"result:%d",result);

打印結(jié)果：

result:1

3、不考慮大小寫比較字符串

復(fù)制代碼代碼如下:

BOOL result = [first compare:second
                     options:NSCaseInsensitiveSearch | NSNumericSearch] == NSOrderedSame;
NSLog(@"result:%d",result);

打印結(jié)果：

result:1

五、改變字符串大小寫

復(fù)制代碼代碼如下:

NSString *aString = @"A String"; 
NSString *string = @"String"; 
//大寫
NSLog(@"aString:%@",[aString uppercaseString]);
//小寫
NSLog(@"string:%@",[string lowercaseString]);
//首字母大小寫
NSLog(@"string:%@",[string capitalizedString]);

打印結(jié)果：

aString:A STRINGstring:stringstring:String

六、在字符串中搜索子串

復(fù)制代碼代碼如下:

NSString *string1 = @"This is a string";
NSString *string2 = @"string";
NSRange range = [string1 rangeOfString:string2];
NSUInteger location = range.location;
NSUInteger leight = range.length;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%li,Leight:%li",location,leight]];
NSLog(@"astring:%@",astring);
[astring release];

打印結(jié)果：