如何在 Dart 中使用正则表达式? [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与特定的 RegEx 匹配.但是,我从应用程序的 JavaScript 版本复制的 RegEx 总是 在 Flutter 应用程序中返回 false.我在 regexr 上验证了 RegEx 是有效的,而且这个 RegEx 已经在 JavaScript 应用程序中使用,所以它应该正确.
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!
正则表达式:/^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
我认为您试图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 不区分大小写被声明为 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());
给出:
allMatches : (Instance of '_MatchImplementation')
firstMatch : Instance of '_MatchImplementation'
hasMatch : true
stringMatch : WS://127.0.0.1:56789
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