OC中的那些String

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/--------操作字串--NSString(靜態字串)---------------------

NSString * a = @"a+b+c+a+b+d";

        NSArray  * m = [a componentsSeparatedByString:@"+"];//字串根據某個字串拆分

NSRange x = [a rangeOfString:@"b"];//尋找子字串在總字串的範圍

        NSLog(@"%lu, %lu", x.location , x.length);

NSString * r = [a stringByReplacingOccurrencesOfString:@"+" withString:@"-"];//把某個字串替換成另一個字串

        NSLog(@"%@", r);

NSString * str = @"wo shi xiao hong jun!";

        NSString * result = [str uppercaseString];//小寫字母變成大寫

        NSLog(@"%@", result);

        NSString * result1 = [str capitalizedString];//第一個單詞變成大寫

        NSLog(@"%@", result1);

        NSString * result2 = [result lowercaseString];//大寫字母改為小寫

        NSLog(@"%@", result2);

    NSString * Beijing= @"河南";        //字串的聲明

    NSString * [email protected]"河南歡迎您a"; //[NSString stringWithFormat:@"I am ‘%@‘", Beijing];     //字串格式化

    NSString * zhui = [Beijing stringByAppendingString:@"啦啦啦"];        //字串追加

    bool b=[Beijing isEqualToString:log];                               //字串比較

    NSString * hh = @"http://www.cnblog.com";

    if([hh hasPrefix:@"http"]){                                          //尋找以http開頭的字串

        NSLog(@"含有http");

    }else{

        NSLog(@"沒有http");
    }
    NSString * ss = @"123";

    int a = [ss intValue];                                   //字串轉int型

    double dd = [ss doubleValue];                          //字串轉double型

    NSLog(@"%g", dd);

//字串轉數組 

    NSString * zifuchuan [email protected]"one, two, three, four";

    NSLog(@"string:%@", zifuchuan);

    NSArray * array = [zifuchuan componentsSeparatedByString:@","];//用,把字元分成數字元素

//    NSLog(@"array:%@", array);                             //輸出整個數組中所有元素 

    NSString * value = [array objectAtIndex:0];          //取出第0個元素

    NSLog(@"value:%@", value);

//數組轉字串

    NSString * zifuchuan2 = [array componentsJoinedByString:@","];//用,把各個數字組成字串

    NSLog(@"zifuchuan2:%@", zifuchuan2);
       
//-substringToIndex: 從字串的開頭一直截取到指定的位置，但不包括該位置的字元

NSString * string1 = @"This is a string";

NSString * string2 = [string1 substringToIndex:3];

NSLog(@"string2:%@",string2);

//-substringFromIndex: 以指定位置開始（包括指定位置的字元），並包括之後的全部字元

NSString * string1 = @"This is a string";

NSString * string2 = [string1 substringFromIndex:3];

NSLog(@"string2:%@",string2);

//-substringWithRange: //按照所給出的位置，長度，任意地從字串中截取子串

NSString * string1 = @"This is a string";

NSString * string2 = [string1 substringWithRange:NSMakeRange(0, 4)];//0帶表下標,4表示長度

NSLog(@"string2:%@",string2);

//--------操作動態字串--NSMutableString----------------------------------------------------

    NSMutableString * mstr = [[NSMutableString alloc] init];

    NSString * str1 = @"This is a example.";

    //建立可變字串

    mstr = [NSMutableString stringWithString:str1];

//插入字元

    [mstr insertString:@"very easy " atIndex:10];

    //刪除一些字元

    [mstr deleteCharactersInRange:NSMakeRange(10,5)];

    //尋找並刪除

    NSRange substr = [mstr rangeOfString:@"example"];             //字串尋找,可以判斷字串中是否有

    if (substr.location != NSNotFound) {

        [mstr deleteCharactersInRange:substr];

    }

    //重新設定字串

    [mstr setString:@"This is string AAA"];

    //替換字串

    [mstr replaceCharactersInRange:NSMakeRange(15, 2) withString:@"BBB"];   //從第15個字串處替換掉後2個字串
   
    //尋找第一個並替換

    NSString * search = @"This is";

    NSString * replace = @"An example of";

    substr = [mstr rangeOfString:search];

    if (substr.location != NSNotFound) {

        [mstr replaceCharactersInRange:substr withString:replace];      //把第1個遇到的substr替換為replace

        NSLog(@"%@", mstr);
    }
   
    //尋找全部匹配的，並替換

    search = @"a";

    replace = @"X";

    substr = [mstr rangeOfString:search];

    while (substr.location != NSNotFound) {

        [mstr replaceCharactersInRange:substr withString:replace];

        substr = [mstr rangeOfString:search];
    }

    NSLog(@"%@", mstr);