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：处理字母等其他元素只需将NSCharacterSet的值改变即可。
复制代码
+ (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、用字符将NSArray中的元素拼接起来
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NSArray *array = [NSArray arrayWithObjects:@"hello",@"world",nil];
//如要用,:等字符串拼接，只需将下面的@" "空格换成@","或@":"即可
NSString *string = [array componentsJoinedByString:@" "];
NSLog(@"string = %@",string);
打印结果：
hello world
三、截取子串：
这里以获取时间为例，利用NSDate获取到当前时间时，有时候只需要日期或者只需要时间
1、从字符串开头截取到指定的位置，如
复制代码//获取到当前日期时间
NSDate *date = [NSDate date];
//定义日期格式,此处不重点讨论NSDate，故不详细说明，在后面会详细讨论
NSDateFormatter *dateformatter = [[NSDateFormatter alloc] init];
