oc字符串的一些使用方法

1.字符串创建一

  NSString *str=@"asdfghjkl";

  NSLog(@"%@",str);

 

2.字符串创建二

  NSString *str=[[NSString alloc]initWithFormat:@"abc"];

  NSLog(@"%@",str);

 

3.判断字符串的长度

  NSString *str=[[NSString alloc]initWithFormat:@"abc"];

  NSLog(@"%ld",str.length);

 

4.取第几个位置的字符

    NSString *str=@"asdfghjkl";

  unichar ch= [str characterAtIndex:4];

  NSLog(@"%c",ch);

 

5.字符串的截取

  NSString *str1=@"全球领先的移动设备操作系统";

（1）.截取定位以及之后的字符  字符串的定位从零开始

  NSString *str2=[str1 substringFromIndex:9];

  NSLog(@"%@",str2);

       

（2）.截取定位之前的字符

  NSString *str3=[str1 substringToIndex:4];

  NSLog(@"%@",str3);

     

（3）.截取中间字符

  NSRange range;

  range.location=5; //表示定位

  range.length=4;   //表示截取字符串范围

  NSString *str4=[str1 substringWithRange:range];

  NSLog(@"%@",str4);

 

（4）.-substringWithRange: //按照所给出的位置，长度，任意地从字符串中截取子串   

    NSString *str2 = [str1 substringWithRange:NSMakeRange(0, 4)]; 

    NSLog(@"str2:%@",str2);

 

6.compar的比较

//        //字符串的比较
//        NSString *str5=@"asdf";
//        NSString *str6=@"ASDF";
//        //不忽略大小写
//        NSComparisonResult result=[str5 compare:str6];
//        NSLog(@"%ld",result);
//        //忽略大小写
//        NSComparisonResult result1=  [str5  compare:str6 options:NSCaseInsensitiveSearch];

//        NSLog(@"%ld",result1);

 

7.isEqualToString方法的比较

//        NSString *str5=@"asdf";

//        NSString *str6=@"ASDF";

//        BOOL bol=[str5 isEqualToString:str6];

//        NSLog(@"%d",bol);

 

8. 字符串查找

//        NSString *str7=@"www.asdfghj.com";
//        BOOL bol1=[str7 hasPrefix:@".com"];

//        NSLog(@"%d",bol1);

 

//        //字符串的追加
//        NSString *str9=@"https://";
//        NSString *str10=[str9 stringByAppendingString:str7];
//        NSLog(@"%@",str10);
//        //字符串的替换
//        NSString *str11=[str7 stringByReplacingOccurrencesOfString:@"www." withString:@"https://"];
//        NSLog(@"%@",str11);
//        NSRange range1=[str7 rangeOfString:@"asdfghj"];
//        NSString str12=[str7 stringByReplacingCharactersInRange: withString:@"*****"];
       
//        //字符串的转换
//        NSString *num=@"123456789";
//        NSLog(@"%f",num.doubleValue*10);
//       
//        //oc字符串装换成c字符
//        NSString *str8=@"asdfgh";
//        NSLog(@"%s",str8.UTF8String);
//       
//        //c字符串装换成oc字符
//        char * ch1="asdfghjk";
//        //方法一
//        NSLog(@"%@",[NSString stringWithUTF8String:ch1]);
//        //方法二

//        NSLog(@"%@",@(ch1));

 

可变字符串

NSMutableString *str6=[NSMutableString stringWithCapacity:100];

        [str6 appendString:@"aaa"];

        [str6 appendFormat:@"%d",3];

        [str6 replaceCharactersInRange:[str6 rangeOfString:@"3"] withString:@".."];

//        [str6 deleteCharactersInRange:[str6 rangeOfString:@".."]];

        NSLog(@"%@",str6);