如何解析Objective C中的字符串

Question

有人可以帮我从Objective C中的字符串“/ Date（1242597600000）/”中提取int时间戳值

我想得到1242597600000。

THX

Answer 1

一种简单的方法：

NSString *timestampString = @"\/Date(1242597600000)\/";
NSArray *components = [timestampString componentsSeparatedByString:@"("];
NSString *afterOpenBracket = [components objectAtIndex:1];
components = [afterOpenBracket componentsSeparatedByString:@")"];
NSString *numberString = [components objectAtIndex:0];
long timeStamp = [numberString longValue];

或者，如果您知道字符串的长度和格式始终相同，则可以使用：

NSString *numberString = [timestampString substringWithRange:NSMakeRange(7,13)];

另一种方法：

NSRange openBracket = [timestampString rangeOfString:@"("];
NSRange closeBracket = [timestampString rangeOfString:@")"];
NSRange numberRange = NSMakeRange(openBracket.location + 1, closeBracket.location - openBracket.location - 1);
NSString *numberString = [timestampString substringWithRange:numberRange];

Answer 2

有多种方法可以做到这一点。以下是使用NSScanner的建议;

NSString *dateString = @"\/Date(1242597600000)\/";
NSScanner *dateScanner = [NSScanner scannerWithString:dateString];
NSInteger timestamp;

if (!([dateScanner scanInteger:&timestamp])) {
    // scanInteger returns NO if the extraction is unsuccessful
    NSLog(@"Unable to extract string");
}

// If no error, then timestamp now contains the extracted numbers.

Answer 3

NSCharacterSet* nonDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
NSString* digitString = [timestampString stringByTrimmingCharactersInSet:nonDigits];
return [digitString longValue];