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  • objectivec中的NSString操作

      //1、创建常量字符串。
        NSString *astring = @"This is a String!";

     

    //2、创建空字符串,给予赋值。

        NSString *astring = [[NSString alloc] init];
        astring = @"This is a String!";
        NSLog(@"astring:%@",astring);
      [astring release];

     

    //3、在以上方法中,提升速度:initWithString方法

        NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
        NSLog(@"astring:%@",astring);
        [astring release];

     

     //4、用标准c创建字符串:initWithCString方法

        char *Cstring = "This is a String!";
        NSString *astring = [[NSString alloc] initWithCString:Cstring];
        NSLog(@"astring:%@",astring);
        [astring release];

     

        //5、创建格式化字符串:占位符(由一个%加一个字符组成)

        int i = 1;
        int j = 2;
        NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"%d.This is %i string!",i,j]];
        NSLog(@"astring:%@",astring);
        [astring release];

     

        //6、创建临时字符串

        NSString *astring;
        astring = [NSString stringWithCString:"This is a temporary string"];
        NSLog(@"astring:%@",astring);


        NSString *path = @"astring.text";
        NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
        NSLog(@"astring:%@",astring);
        [astring release];


        NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
        NSLog(@"astring:%@",astring);
        NSString *path = @"astring.text";    
        [astring writeToFile: path atomically: YES];
        [astring release];

        //用C比较:strcmp函数

        char string1[] = "string!";
        char string2[] = "string!";
        if(strcmp(string1, string2) = = 0)
        {
            NSLog(@"1");
        }

       //isEqualToString方法    
        NSString *astring01 = @"This is a String!";
        NSString *astring02 = @"This is a String!";
        BOOL result = [astring01 isEqualToString:astring02];
        NSLog(@"result:%d",result);

     

       //compare方法(comparer返回的三种值)    
        NSString *astring01 = @"This is a String!";
        NSString *astring02 = @"This is a String!";    
        BOOL result = [astring01 compare:astring02] = = NSOrderedSame;    
        NSLog(@"result:%d",result);    


        //NSOrderedSame 判断两者内容是否相同

        NSString *astring01 = @"This is a String!";
        NSString *astring02 = @"this is a String!";
        BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;    

        NSLog(@"result:%d",result);


        //NSOrderedAscending 判断两对象值的大小(按字母顺序进行比较,astring02大于astring01为真)

        NSString *astring01 = @"this is a String!";
        NSString *astring02 = @"This is a String!";
        BOOL result = [astring01 compare:astring02] = = NSOrderedDescending;    
        NSLog(@"result:%d",result);     


        //NSOrderedDescending 判断两对象值的大小(按字母顺序进行比较,astring02小于astring01为真)

    //不考虑大 小写比较字符串1
        NSString *astring01 = @"this is a String!";
        NSString *astring02 = @"This is a String!";
        BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame;    
        NSLog(@"result:%d",result);     


        //NSOrderedDescending判断两对象值的大小(按字母顺序进行比较,astring02小于astring01为真)

    //如何判断字符串为空

    NSString *urlString = [urlInput stringValue];

     
    if (!urlString) { 
     
     
    NSLog( @”NO INPUT.” );

     
    } else { 
     
    if ([urlString length] == 0 ) {

     
    NSLog( @”NO INPUT.” );

     
    } else {

     
    }

     

     

     

    Convert NSString to int

    1NSString *aNumberString = @"123";
    2int i = [aNumberString intValue];

     

    Convert int to NSString

    1int aNumber = 123;
    2NSString *aString = [NSString stringWithFormat:@"%d", aNumber];
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  • 原文地址:https://www.cnblogs.com/moonvan/p/2210500.html
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