如何在Dart中使用RegEx？ [英] How to use RegEx in Dart?

问题描述

在Flutter应用程序中，我需要检查字符串是否匹配特定的RegEx。但是，我从应用程序始终的JavaScript版本复制的RegEx在Flutter应用程序中返回false。我在 regexr 上验证了RegEx有效，并且正则表达式已在JavaScript应用程序中使用，因此应该

In a Flutter application, I need to check if a string matches a specific RegEx. However, the RegEx I copied from the JavaScript version of the app always returns false in the Flutter app. I verified on regexr that the RegEx is valid, and this very RegEx is already being used in the JavaScript application, so it should be correct.

感谢任何帮助！

RegEx： / ^ WS { 1,2}：\ / \ / \d {1,3} \.\d {1,3} \.\d {1,3} \.\d {1， 3}：56789 / i

测试代码：

RegExp regExp = new RegExp(
  r"/^WS{1,2}:\/\/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}:56789/i",
  caseSensitive: false,
  multiLine: false,
);
print("allMatches : "+regExp.allMatches("WS://127.0.0.1:56789").toString());
print("firstMatch : "+regExp.firstMatch("WS://127.0.0.1:56789").toString());
print("hasMatch : "+regExp.hasMatch("WS://127.0.0.1:56789").toString());
print("stringMatch : "+regExp.stringMatch("WS://127.0.0.1:56789").toString());

输出：

allMatches : ()
firstMatch : null
hasMatch : false
stringMatch : null

推荐答案

我认为您已尝试在原始表达式字符串中包含选项，而您已经将其作为RegEx的参数（/ i用于区分大小写的声明为caseSensitive ：false）。

I think you tried to include options in the raw expression string while you already have it as parameters to RegEx ( /i for case insensitivity is declared as caseSensitive: false).

// Removed /i at the end
// Removed / in front - Thanks to Günter for warning
RegExp regExp = new RegExp(
  r"^WS{1,2}:\/\/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}:56789",
  caseSensitive: false,
  multiLine: false,
);
print("allMatches : "+regExp.allMatches("WS://127.0.0.1:56789").toString());
print("firstMatch : "+regExp.firstMatch("WS://127.0.0.1:56789").toString());
print("hasMatch : "+regExp.hasMatch("WS://127.0.0.1:56789").toString());
print("stringMatch : "+regExp.stringMatch("WS://127.0.0.1:56789").toString());

礼物：

allMatches : (Instance of '_MatchImplementation')
firstMatch : Instance of '_MatchImplementation'
hasMatch : true
stringMatch : WS://127.0.0.1:56789

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