NSString 常用操作範例

1.字串比較
NSString *str1 = [[NSString alloc]initWithString:@"I am String1"];
NSString *str2 = [[NSString alloc]initWithString:@"I am String2"];
NSLog(@"%@ 與 %@ 是否相同: %@", str1, str2, [str1 isEqualToString:str2] ? @"Y":@"N");
[str1 release];
[str2 release];


2.字串比較(不區分大小寫)
NSString *str1 = [[NSString alloc]initWithString:@"I am String1"];
NSString *str2 = [[NSString alloc]initWithString:@"i am string1"];
NSLog(@"%@ 與 %@ 是否相同(不考慮大小寫): %@", str1, str2,
[str1 caseInsensitiveCompare:str2]==NSOrderedSame ? @"Y":@"N");
[str1 release];
[str2 release];

3.搜尋字串
NSString *str1 = [[NSString alloc]initWithString:@"This is an apple"];
//此處NSRange 為區分大小寫
NSRange searchString1 = [str1 rangeOfString:@"apple"];
NSRange searchString2 = [str1 rangeOfString:@"orange"];
NSLog(@"%@ 是否有apple字串: %@",str1, searchString1.location == NSNotFound ? @"N" : @"Y" );
NSLog(@"%@ 是否有orange字串: %@",str1, searchString2.location == NSNotFound ? @"N" : @"Y" );
[str1 release];

4.取出字串
NSString *str1 = [[NSString alloc]initWithString:@"this is a string"];
NSLog(@"%@ 取出從頭自第2位(不包含第2位)的字串: %@",str1, [str1 substringToIndex:1]);
NSLog(@"%@ 取出第2位(包含) 後所有字串: %@",str1, [str1 substringFromIndex:1]);
NSLog(@"%@ 取出第3位至第7位的字串: %@",str1, [str1 substringWithRange:NSMakeRange(5,4)]);
[str1 release];

5.替換字串
NSString *string1 = [[NSString alloc]initWithString:@"this is a book"];
NSString *string2 = [[NSString alloc]initWithString:@"pen"];
NSLog(@"%@ 替換後 %@",string1,
[string1 stringByReplacingOccurrencesOfString:@"book" withString:@"pen"]);
[string1 release];
[string2 release];

6.字串轉成array
NSString *str1 = [[NSString alloc]initWithString:@"apple,orange,cat,dog,bird"];
NSLog(@"%@",[str1 componentsSeparatedByString:@","]);
[str1 release];

7.array轉成字串
NSArray *array = [[NSArray alloc]initWithObjects:@"apple",@"orange",@"cat",@"bird",nil];
NSLog(@"%@",[array componentsJoinedByString:@","]);
[array release];