查找 5 位代码的正则表达式 [英] Regex Expression to Find 5-Digit Code

问题描述

尝试根据以下条件查找模式匹配:

• 字符串长度为 5 个字符
• 字符 [0] = 字母/数字
• 字符 [1] = 字母
• 字符 [2-4] = 数字

我不明白为什么22222"适用于这个表达式?

 p = r'(\w|\d)(\w)(\d){3,}'m = re.match(p, "AA012") # 按预期工作-->'AA012'm = re.match(p, "1A222") # 按预期工作-->'1A222'm = re.match(p, "22222") # 没有按预期工作！-->'22222'

我的正则表达式语法中缺少什么?

解决方案

\w 匹配字母 和 数字(以及下划线).

如果您想匹配仅个字母，请使用[a-zA-Z]:

r'\w[a-zA-Z]\d{3,}'

匹配一个字母或数字(或下划线)，然后是一个字母，然后是 3 个数字.

演示:

<预><代码>>>>进口重新>>>p = r'\w[a-zA-Z]\d{3,}'>>>重新匹配(p，22222")>>>重新匹配(p，AA012")<_sre.SRE_Match 对象在 0x105aca718>>>>重新匹配(p，1A222")<_sre.SRE_Match 对象在 0x105aca780>>>>重新匹配(p，_A222")<_sre.SRE_Match 对象在 0x105aca718>

如果下划线有问题，请使用:

r'[a-zA-Z\d][a-zA-Z]\d{3}'

Trying to find pattern matches based on the following conditions:

• Length of string is 5 characters
• Char [0] = Letter/Number
• Char [1] = Letter
• Char [2-4] = Number

I don't understand why "22222" works for this expression?

 p = r'(\w|\d)(\w)(\d){3,}'
 m = re.match(p, "AA012")    # Works as expected
 --> 'AA012'

 m = re.match(p, "1A222")    # Works as expected
 --> '1A222'

 m = re.match(p, "22222")    # Does NOT work as expected!
 --> '22222'

What am I missing in my regex expression syntax?

解决方案

\w matches letters and digits (as well as underscores).

Use [a-zA-Z] if you want to match only letters:

r'\w[a-zA-Z]\d{3,}'

which matches a letter or digit (or an underscore), then a letter, then 3 digits.

Demo:

>>> import re
>>> p = r'\w[a-zA-Z]\d{3,}'
>>> re.match(p, "22222")
>>> re.match(p, "AA012")
<_sre.SRE_Match object at 0x105aca718>
>>> re.match(p, "1A222")
<_sre.SRE_Match object at 0x105aca780>
>>> re.match(p, "_A222")
<_sre.SRE_Match object at 0x105aca718>

If the underscore is a problem, use:

r'[a-zA-Z\d][a-zA-Z]\d{3}'

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