iOS NSSting 關於字串的尋找、截取、拆分、替換、驗證、改變大小寫、編碼解碼等

1、尋找

NSString*str = @"bfjfnnfkanfknf";

NSRange range = [str rangeOfString:@"111"];

if (range.location == NSNotFound)

{

      NSLog(@"str中沒有找到111");

}else {

     NSLog(@"搜尋範圍%@",NSStringFromRange(range));

}

下面的方法在ios8.0以後使用，也是判斷是否包含某個字串

BOOL result = [@“123" containsString:@"2"]; 2、截取

NSString*bStr = [str substringWithRange:NSMakeRange(loc,2)];

loc表示從第幾個字元開始，2表示截取兩個字元；

從首字元開始截取n個字元: [str substringToIndex:n]; 從第n+1位開始截取,至字串最後: [str substringFromIndex:n];
3、拆分

NSString*string =@"面朝大海/春暖花開";

NSArray*array = [string componentsSeparatedByString:@"/"];//從字元/中分隔成2個元素的數組

NSLog(@"array1 ==== %@",[array firstObject]);

NSLog(@"array2 ==== %@",[array lastObject]); 列印結果：array1 = 面朝大海，array2 = 春暖花開 4.替換

NSString*str =@"12345678";

NSString*replacedStr = [str stringByReplacingOccurrencesOfString:@"345"withString:@"想要替換成的字串"];

NSLog(@"replacedStr ==== %@", replacedStr);

列印結果:

replacedStr ==== 12想要替換成的字串678 5.驗證

NSString*str1 =@"http:www.baidu.com";

BOOL a = [str1 hasPrefix:@"http"];//是否是以http開頭

BOOL b = [str1 hasSuffix:@"com"];//檔案路徑是否以com結尾

NSLog(@"a ===== %d ,b ==== %d",a,b);

列印結果:

a ===== 1 ,b ==== 1 6.轉成數字

[str boolValue];

[str integerValue]; 7.改變字串的大小寫

NSString* str2 =@"beiJING";

NSString*da = [str2 uppercaseString];//轉成大寫

NSString*xiao = [str2 lowercaseString];//轉成小寫

NSString*shouDa = [str2 capitalizedString];//首字母大寫，其餘小寫

NSLog(@"\n大寫==%@\n小寫=== %@\n首字母大寫其餘小寫=== %@",da,xiao,shouDa);

列印結果:

大寫==BEIJING

小寫=== beijing

首字母大寫其餘小寫=== Beijing 8.編碼，解碼

編碼:

NSString*hStr =@"你好啊";

NSString*hString = [hStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSLog(@"hString === %@",hString);

解碼:

NSString*str3 =@"\u5982\u4f55\u8054\u7cfb\u5ba2\u670d\u4eba\u5458\uff1f";

NSString*str5 = [str3stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSLog(@"string ==== %@",str5);

列印結果:

hString === %E4%BD%A0%E5%A5%BD%E5%95%8A

string ====如何聯絡客服人員。