如何编写匹配指定格式的带国家代码英国电话号码的RegEx？

Got it, let's break down how to build the exact regex you need. The target format has a clear, consistent structure, so we can craft a pattern that enforces every part of it—no extra characters allowed, no missing elements.

The Regex Pattern #

^\+\d{1,3} \(\d\) \d{2} \d{4} \d{4}$

What Each Part Does #

Let's unpack this piece by piece to make sure you understand how it enforces the format:

• ^: Anchors the match to the start of the string (ensures nothing comes before the +)
• \+: Matches the literal + sign (we escape it with \ because + is a special character in regex)
• \d{1,3}: Matches 1 to 3 digits for the country code (covers common international prefixes like 1, 44, 86)
• : Matches a single literal space (strictly enforces the space after the country code)
• \(\d\): Matches a single digit wrapped in parentheses (like (0) in your example—\( and \) escape the literal parentheses since they're special in regex)
• : Another single literal space, enforcing the gap after the parenthesized digit
• \d{2}: Matches exactly 2 digits for the area code (like 20 in your example)
• : Single space after the area code
• \d{4}: Matches exactly 4 digits for the first number segment
• : Single space between the two number segments
• \d{4}$: Matches exactly 4 digits for the final segment, with $ anchoring the match to the end of the string (ensures nothing comes after this)

Example Matches #

This regex will correctly match any number following the same structure, like:

• +44 (0)20 1234 5678 (your original example)
• +86 (0)10 9876 5432
• +1 (1)21 5555 1234

If You Need to Adjust the Format #

If you need to tweak parts of the pattern (e.g., allow more digits in the parenthesized section, or a different area code length), you can modify the quantifiers:

• To allow 1-2 digits in the parentheses: change \(\d\) to \(\d{1,2}\)
• To use a 3-digit area code: change \d{2} to \d{3}

内容的提问来源于stack exchange，提问作者Muppet