(IOS)处理字符串，使其首字母大写

 NSString *str = @"abcdefghijklmn";

    NSString*resultStr;

    if(str && str.length>0) {

        resultStr = [strstringByReplacingCharactersInRange:NSMakeRange(0,1) withString:[[str substringToIndex:1] capitalizedString]];

    }

    NSLog(@"%@", resultStr);