javascript - 正则表达式 (JavaScript) : match feet and/or inches

Question

我正在尝试匹配英尺和英寸，但我无法设法得到“和/或”，所以如果前半部分是正确的，它会验证:

代码:(在 javascript 中)

var pattern = "^(([0-9]{1,}\')?([0-9]{1,}\x22)?)+$";

function testing(input, pattern) {
        var regex = new RegExp(pattern, "g");
        console.log('Validate '+input+' against ' + pattern);
        console.log(regex.test(input));
    }

有效的测试应该是:

• 1'
• 1'2"
• 2"
• 2(假设为英寸)

无效应该是:* 其他任何东西，包括空的* 1'1'

但是我的正则表达式匹配无效的1'1'。

Answer 1

删除末尾的 +(现在允许多个 feet/inches 实例)并检查空字符串或非法条目，如 1'2使用单独的 negative lookahead assertion .我还更改了正则表达式，因此第 1 组包含英尺，第 2 组包含英寸(如果匹配):

^(?!$|.*\'[^\x22]+$)(?:([0-9]+)\')?(?:([0-9]+)\x22?)?$

测试一下 live on regex101.com .

解释:

^          # Start of string
(?!        # Assert that the following can't match here:
 $         # the end of string marker (excluding empty strings from match)
|          # or
 .*\'      # any string that contains a '
 [^\x22]+  # if anything follows that doesn't include a "
 $         # until the end of the string (excluding invalid input like 1'2)
)          # End of lookahead assertion
(?:        # Start of non-capturing group:
 ([0-9]+)  # Match an integer, capture it in group 1
 \'        # Match a ' (mandatory)
)?         # Make the entire group optional
(?:        # Start of non-capturing group:
 ([0-9]+)  # Match an integer, capture it in group 2
 \x22?     # Match a " (optional)
)?         # Make the entire group optional
$          # End of string