一.NSString常見創建

1.聲明一個常量字符串

1 NSString *str = @"abc";

2.通過構造方法創建字符串

1 NSString *str1 = [[NSString alloc]initWithString:@"abc"]; 2 NSString *str2 = [[NSString alloc]initWithUTF8String:"abc"]; 3 NSString *str3 = [[NSStringalloc]initWithFormat:@"%@%c",@"ab",'c'];

3.通過類方法創建字符串

1 NSString *str1 = [NSString stringWithString:@"abc"]; 2 NSString *str2 = [NSString stringWithUTF8String:"abc"]; 3 NSString *str3 = [NSString stringWithFormat:@"%@%c",@"ab",'c'];

二.字符串比較

1.判斷兩個字符串是否相等(isEqualToString)

1 NSString *str1 = @"1234567890"; 2 NSString *str2 = @"1234567890"; 3 BOOL ret = [str1 isEqualToString:str2]; 4 NSLog(@"ret is %d",ret);

輸出結果:

2016-06-27 10:56:56.284 OcTest[561:282681] ret is 1 Program ended with exit code: 0

2.兩個字符串比較函數(compare)

NSString *str1 = @"1234567890";NSString *str2 = @"12345";NSComparisonResult result = [str1 compare:str2];if (result == NSOrderedAscending){NSLog(@"str1 < str2");}else if (result == NSOrderedDescending){NSLog(@"str1 > str2");}else if (result == NSOrderedSame){NSLog(@"str1 = str2");}

　　輸出結果:

2016-06-27 11:03:48.707 OcTest[597:310397] str1 > str2 Program ended with exit code: 0

三.字符串截取

首先創建一個字符串，下面以str1為例:

1 NSString *str1 = @"1234567890";

1.截取到第六位(substringToIndex)

NSString *str = [str1 substringToIndex:6]; NSLog(@"str is %@",str);

　　輸出結果:

2016-06-27 11:12:11.284 OcTest[637:341212] str is 123456 Program ended with exit code: 0

2.從第六位開始截取(substringFromIndex)

NSString *str = [str1 substringFromIndex:6]; NSLog(@"str is %@",str);

　　輸出結果:

2016-06-27 11:15:12.630 OcTest[664:356189] str is 7890 Program ended with exit code: 0

3.字符串范圍截取(substringWithRange)

NSString *str = [str1 substringWithRange:NSMakeRange(0, 5)]; NSLog(@"str is %@",str);

　　輸出結果:

2016-06-27 11:17:38.833 OcTest[674:366407] str is 12345 Program ended with exit code: 0

四.一個字符串在另一個字符串中的位置(rangeOfString)

首先新創建一個字符串str2

NSString *str2 = @"1234"; NSRange range = [str1 rangeOfString:str2]; NSLog(@"range loc is %zd,range length is %zd",range.location,range.length);

　　輸出結果:

2016-06-27 11:24:01.916 OcTest[684:394116] range loc is 0,range length is 4 Program ended with exit code: 0

五.字符串查詢

NSString *str = @"f232423dsgerh23wd3349k00cv3";NSScanner *scanner = [NSScanner scannerWithString:str];while(![scanner isAtEnd] && ++scanner.scanLocation){int result;if([scanner scanInt:&result]){NSLog(@"%d",result);}}

　　輸出結果：

2016-07-01 15:10:15.231 OCString[851:320391] 232423 2016-07-01 15:10:15.232 OCString[851:320391] 23 2016-07-01 15:10:15.232 OCString[851:320391] 3349 2016-07-01 15:10:15.232 OCString[851:320391] 0 2016-07-01 15:10:15.232 OCString[851:320391] 3 Program ended with exit code: 0

　　

　　

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轉載于:https://www.cnblogs.com/kaihuacheng/p/5615394.html

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