正则表达式 - 在字符串中查找大写单词

问题描述

我正在尝试学习如何使用正则表达式，但有一个问题.假设我有字符串

line = 'Cow Apple think Woof`

我想看看 line 是否至少有两个以大写字母开头的单词(当然有).在 Python 中，我尝试执行以下操作

导入重新test = re.search(r'(\b[A-Z]([a-z])*\b){2,}',line)打印(布尔(测试))

但是打印False.如果我改为

test = re.search(r'(\b[A-Z]([a-z])*\b)',line)

我发现 print(test.group(1)) 是 Cow 但 print(test.group(2)) 是 w，第一个匹配的最后一个字母(test.group 中没有其他元素).

对于查明此问题和/或如何更好地解决问题有任何建议吗?

解决方案

由于内括号，匹配的最后一个字母在组中.放下那些，你会没事的.

>>>t = re.findall('([A-Z][a-z]+)', 行)>>>吨['牛'，'苹果'，'汪']>>>t = re.findall('([A-Z]([a-z])+)', 行)>>>吨[('Cow', 'w'), ('Apple', 'e'), ('Woof', 'f')]

大写单词的数量当然是len(t).

I'm trying to learn how to use regular expressions but have a question. Let's say I have the string

line = 'Cow Apple think Woof`

I want to see if line has at least two words that begin with capital letters (which, of course, it does). In Python, I tried to do the following

import re
test = re.search(r'(\b[A-Z]([a-z])*\b){2,}',line)
print(bool(test))

but that prints False. If I instead do

test = re.search(r'(\b[A-Z]([a-z])*\b)',line)

I find that print(test.group(1)) is Cow but print(test.group(2)) is w, the last letter of the first match (there are no other elements in test.group).

Any suggestions on pinpointing this issue and/or how to approach the problem better in general?

解决方案

The last letter of the match is in group because of inner parentheses. Just drop those and you'll be fine.

>>> t = re.findall('([A-Z][a-z]+)', line)
>>> t
['Cow', 'Apple', 'Woof']
>>> t = re.findall('([A-Z]([a-z])+)', line)
>>> t
[('Cow', 'w'), ('Apple', 'e'), ('Woof', 'f')]

The count of capitalised words is, of course, len(t).

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