iOS改变字母的大小写

使用lowercaseString,uppercaseString 

-(void)test{

    NSString * str = @"person";

    NSString * str1 = [str lowercaseString];

    NSString * str2 = [str uppercaseString];

    NSLog(@"%@,%@",str1,str2);

　

    NSString * text = @"Hello World";

    text = [text stringByReplacingCharactersInRange:NSMakeRange(0, 1) withString:[[text substringToIndex:1]lowercaseString ]];

    NSLog(@"text:%@",text);

}

 打印结果:

2016-07-29 11:49:47.455 改变字母大小写[1058:50425] str1:person

2016-07-29 11:49:47.455 改变字母大小写[1058:50425] str2:PERSON

2016-07-29 11:49:47.456 改变字母大小写[1058:50425] text:hello World