从查询字符串中删除一个参数的正则表达式 [英] Regular expression to remove one parameter from query string
问题描述
我正在寻找一个正则表达式来从查询字符串中删除单个参数，如果可能的话，我想在单个正则表达式中完成.
I'm looking for a regular expression to remove a single parameter from a query string, and I want to do it in a single regular expression if possible.
假设我想删除 foo 参数.现在我用这个:
Say I want to remove the foo parameter. Right now I use this:
/&?foo\=[^&]+/
只要 foo 不是查询字符串中的第一个参数，它就可以工作.如果是，那么我的新查询字符串以与号开头.(例如，foo=123&bar=456"给出&bar=456"的结果.)现在，我只是在检查如果查询字符串以 & 开头，则使用正则表达式，如果是，则将其截断.
That works as long as foo is not the first parameter in the query string. If it is, then my new query string starts with an ampersand. (For example, "foo=123&bar=456" gives a result of "&bar=456".) Right now, I'm just checking after the regex if the query string starts with ampersand, and chopping it off if it does.
边缘情况示例:
Input | Expected Output
-------------------------+--------------------
foo=123 | (empty string)
foo=123&bar=456 | bar=456
bar=456&foo=123 | bar=456
abc=789&foo=123&bar=456 | abc=789&bar=456
<小时>
编辑
好的，正如评论中指出的那样，边缘情况比我最初考虑的要多得多.我得到了以下正则表达式来处理所有这些:
Edit
OK as pointed out in comments there are there are way more edge cases than I originally considered. I got the following regex to work with all of them:
/&foo(\=[^&]*)?(?=&|$)|^foo(\=[^&]*)?(&|$)/
这是从 Mark Byers 的回答中修改的，这就是我接受那个的原因，但 Roger Pate 的意见也有很大帮助.
This is modified from Mark Byers's answer, which is why I'm accepting that one, but Roger Pate's input helped a lot too.
这是我正在使用的全套测试用例，以及测试它们的 Javascript 片段:
Here is the full suite of test cases I'm using, and a Javascript snippet which tests them:
$(function() {
var regex = /&foo(\=[^&]*)?(?=&|$)|^foo(\=[^&]*)?(&|$)/;
var escapeHtml = function (str) {
var map = {
'&': '&',
'<': '<',
'>': '>',
'"': '"',
"'": '''
};
return str.replace(/[&<>"']/g, function(m) { return map[m]; });
};
//test cases
var tests = [
'foo' , 'foo&bar=456' , 'bar=456&foo' , 'abc=789&foo&bar=456'
,'foo=' , 'foo=&bar=456' , 'bar=456&foo=' , 'abc=789&foo=&bar=456'
,'foo=123' , 'foo=123&bar=456' , 'bar=456&foo=123' , 'abc=789&foo=123&bar=456'
,'xfoo' , 'xfoo&bar=456' , 'bar=456&xfoo' , 'abc=789&xfoo&bar=456'
,'xfoo=' , 'xfoo=&bar=456' , 'bar=456&xfoo=' , 'abc=789&xfoo=&bar=456'
,'xfoo=123', 'xfoo=123&bar=456', 'bar=456&xfoo=123', 'abc=789&xfoo=123&bar=456'
,'foox' , 'foox&bar=456' , 'bar=456&foox' , 'abc=789&foox&bar=456'
,'foox=' , 'foox=&bar=456' , 'bar=456&foox=' , 'abc=789&foox=&bar=456'
,'foox=123', 'foox=123&bar=456', 'bar=456&foox=123', 'abc=789&foox=123&bar=456'
];
//expected results
var expected = [
'' , 'bar=456' , 'bar=456' , 'abc=789&bar=456'
,'' , 'bar=456' , 'bar=456' , 'abc=789&bar=456'
,'' , 'bar=456' , 'bar=456' , 'abc=789&bar=456'
,'xfoo' , 'xfoo&bar=456' , 'bar=456&xfoo' , 'abc=789&xfoo&bar=456'
,'xfoo=' , 'xfoo=&bar=456' , 'bar=456&xfoo=' , 'abc=789&xfoo=&bar=456'
,'xfoo=123', 'xfoo=123&bar=456', 'bar=456&xfoo=123', 'abc=789&xfoo=123&bar=456'
,'foox' , 'foox&bar=456' , 'bar=456&foox' , 'abc=789&foox&bar=456'
,'foox=' , 'foox=&bar=456' , 'bar=456&foox=' , 'abc=789&foox=&bar=456'
,'foox=123', 'foox=123&bar=456', 'bar=456&foox=123', 'abc=789&foox=123&bar=456'
];
for(var i = 0; i < tests.length; i++) {
var output = tests[i].replace(regex, '');
var success = (output == expected[i]);
$('#output').append(
'<tr class="' + (success ? 'passed' : 'failed') + '">'
+ '<td>' + (success ? 'PASS' : 'FAIL') + '</td>'
+ '<td>' + escapeHtml(tests[i]) + '</td>'
+ '<td>' + escapeHtml(output) + '</td>'
+ '<td>' + escapeHtml(expected[i]) + '</td>'
+ '</tr>'
);
}
});#output {
border-collapse: collapse;
}
#output tr.passed { background-color: #af8; }
#output tr.failed { background-color: #fc8; }
#output td, #output th {
border: 1px solid black;
padding: 2px;
}<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<table id="output">
<tr>
<th>Succ?</th>
<th>Input</th>
<th>Output</th>
<th>Expected</th>
</tr>
</table>推荐答案
如果你只想在一个正则表达式中做到这一点，你可以这样做:
If you want to do this in just one regular expression, you could do this:
/&foo(=[^&]*)?|^foo(=[^&]*)?&?/
这是因为您需要在 foo=... 之前匹配一个&符号，或者在之后匹配一个符号，或者两者都不匹配，但不能同时匹配两者.
This is because you need to match either an ampersand before the foo=..., or one after, or neither, but not both.
老实说，我认为您这样做的方式更好:在单独的步骤中删除尾随的&符号.
To be honest, I think it's better the way you did it: removing the trailing ampersand in a separate step.
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