blocks|key|819606|text|您必须将正则表达式构建为字符串：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|819607|TEXTO+=+sys.argv[1]
my_regex+=+r"\b(?=\w)"+%2B+re.escape(TEXTO)+%2B+r"\b(?!\w)"

if+re.search(my_regex,+subject,+re.IGNORECASE):
++++etc.|code-block|syntax|javascript|819608|注意re.escape的用法，这样如果您的文本包含特殊字符，它们就不会被解释为特殊字符。|offset|length|style|CODE|819609|entityMap^0|0|0|2|9|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You have to build the regex as a string:

<pre><code>TEXTO = sys.argv[1]
my_regex = r"\b(?=\w)" + re.escape(TEXTO) + r"\b(?!\w)"

if re.search(my_regex, subject, re.IGNORECASE):
 etc.
</code></pre>

Note the use of <code>re.escape</code> so that if your text has special characters, they won't be interpreted as such.

blocks|key|819550|text|if+re.search(r"\b(?<=\w)%25s\b(?!\w)"+%25+TEXTO,+subject,+re.IGNORECASE):|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|819551|这将把TEXTO中的内容作为字符串插入到regex中。|unstyled|819552|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>if re.search(r"\b(?&lt;=\w)%s\b(?!\w)" % TEXTO, subject, re.IGNORECASE):
</code></pre>

This will insert what is in TEXTO into the regex as a string.

blocks|key|604332|text|rx+=+r'\b(?<=\w){0}\b(?!\w)'.format(TEXTO)|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|604333|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>rx = r'\b(?&lt;=\w){0}\b(?!\w)'.format(TEXTO)
</code></pre>

blocks|key|819761|text|我发现通过将多个较小的模式串在一起来构建正则表达式模式非常方便。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|819762|import+re

string+=+"begin:id1:tag:middl:id2:tag:id3:end"
re_str1+=+r'(?<=(\S{5})):'
re_str2+=+r'(id\d%2B):(?=tag:)'
re_pattern+=+re.compile(re_str1+%2B+re_str2)
match+=+re_pattern.findall(string)
print(match)|code-block|syntax|javascript|819763|输出：|819764|[('begin',+'id1'),+('middl',+'id2')]|819765|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I find it very convenient to build a regular expression pattern by stringing together multiple smaller patterns.

<pre><code>import re

string = "begin:id1:tag:middl:id2:tag:id3:end"
re_str1 = r'(?&lt;=(\S{5})):'
re_str2 = r'(id\d+):(?=tag:)'
re_pattern = re.compile(re_str1 + re_str2)
match = re_pattern.findall(string)
print(match)
</code></pre>

Output:

<pre><code>[('begin', 'id1'), ('middl', 'id2')]
</code></pre>

blocks|key|604546|text|我同意以上所有观点，除非：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|604547|sys.argv[1]有点像Chicken\d{2}-\d{2}An\s*important\s*anchor|offset|length|style|CODE|604548|sys.argv[1]+=+"Chicken\d{2}-\d{2}An\s*important\s*anchor"|code-block|syntax|javascript|604549|您不希望使用re.escape，因为在这种情况下，您希望它的行为类似于正则表达式|604550|TEXTO+=+sys.argv[1]

if+re.search(r"\b(?<=\w)"+%2B+TEXTO+%2B+"\b(?!\w)",+subject,+re.IGNORECASE):
++++#+Successful+match
else:
++++#+Match+attempt+failed|604551|entityMap^0|0|0|B|E|15|0|0|6|9|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@$D|U|E|V|F|G]|$D|W|E|X|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|Y|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|Z|8|@$D|10|E|11|F|G]]|9|@]|A|$]]|$1|O|3|P|5|J|7|12|8|@]|9|@]|A|$K|L]]|$1|Q|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|R|$]]

I agree with all the above unless: 

<code>sys.argv[1]</code> was something like <code>Chicken\d{2}-\d{2}An\s*important\s*anchor</code>

<pre><code>sys.argv[1] = "Chicken\d{2}-\d{2}An\s*important\s*anchor"
</code></pre>

you would not want to use <code>re.escape</code>, because in that case you would like it to behave like a regex

<pre><code>TEXTO = sys.argv[1]

if re.search(r"\b(?&lt;=\w)" + TEXTO + "\b(?!\w)", subject, re.IGNORECASE):
 # Successful match
else:
 # Match attempt failed
</code></pre>

blocks|key|819862|text|您可以使用format+grammer+suger尝试其他用法：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|819863|re_genre+=+r'{}'.format(your_variable)
regex_pattern+=+re.compile(re_genre)++|code-block|syntax|javascript|819864|entityMap^0|5|6|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

you can try another usage using <code>format</code> grammer suger:

<pre><code>re_genre = r'{}'.format(your_variable)
regex_pattern = re.compile(re_genre) 
</code></pre>

blocks|key|604595|text|我需要搜索彼此相似的用户名，内德·巴切尔德说的话非常有帮助。然而，当我使用re.compile创建我的搜索词时，我发现我有了更干净的输出：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|604596|pattern+=+re.compile(r"("%2Busername%2B".*):(.*?):(.*?):(.*?):(.*)"
matches+=+re.findall(pattern,+lines)|code-block|syntax|javascript|604597|可以使用以下命令打印输出：|604598|print(matches[1])+#+prints+one+whole+matching+line+(in+this+case,+the+first+line)
print(matches[1][3])+#+prints+the+fourth+character+group+(established+with+the+parentheses+in+the+regex+statement)+of+the+first+line.|604599|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I needed to search for usernames that are similar to each other, and what Ned Batchelder said was incredibly helpful. However, I found I had cleaner output when I used re.compile to create my re search term:

<pre><code>pattern = re.compile(r"("+username+".*):(.*?):(.*?):(.*?):(.*)"
matches = re.findall(pattern, lines)
</code></pre>

Output can be printed using the following:

<pre><code>print(matches[1]) # prints one whole matching line (in this case, the first line)
print(matches[1][3]) # prints the fourth character group (established with the parentheses in the regex statement) of the first line.
</code></pre>

blocks|key|604686|text|您也可以使用format关键字，因为this.Format方法会将{}占位符替换为您作为参数传递给format方法的变量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|604687|if+re.search(r"\b(?=\w)**{}**\b(?!\w)".**format(TEXTO)**,+subject,+re.IGNORECASE):
++++#+Successful+match**strong+text**
else:
++++#+Match+attempt+failed|code-block|syntax|javascript|604688|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can use format keyword as well for this.Format method will replace {} placeholder to the variable which you passed to the format method as an argument. 

<pre><code>if re.search(r"\b(?=\w)**{}**\b(?!\w)".**format(TEXTO)**, subject, re.IGNORECASE):
 # Successful match**strong text**
else:
 # Match attempt failed
</code></pre>

blocks|key|819897|text|更多示例|type|unstyled|depth|inlineStyleRanges|entityRanges|data|819898|我有带有流文件的configus.yml|819899|"pattern":
++-+_(\d{14})_
"datetime_string":
++-+"%25m%25d%25Y%25H%25M%25f"|code-block|syntax|javascript|819900|在python代码中，我使用|819901|data_time_real_file=re.findall(r""%2Bflows[flow]["pattern"][0]%2B"",+latest_file)|819902|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

more example

I have configus.yml
with flows files

<pre><code>"pattern":
 - _(\d{14})_
"datetime_string":
 - "%m%d%Y%H%M%f"
</code></pre>

in python code I use

<pre><code>data_time_real_file=re.findall(r""+flows[flow]["pattern"][0]+"", latest_file)
</code></pre>

blocks|key|819930|text|这是你可以使用的另一种格式(在python+3.7上测试过)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|819931|regex_str+=+r'\b(?<=\w)%25s\b(?!\w)'%25TEXTO|offset|length|style|CODE|819932|我发现当你不能对变量使用{}+(这里用%25s代替)时，它很有用。|819933|entityMap^0|0|0|14|0|C|2|J|2|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|P|8|@$D|Q|E|R|F|G]|$D|S|E|T|F|G]]|9|@]|A|$]]|$1|J|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|K|$]]

here's another format you can use (tested on python 3.7)
<code>regex_str = r'\b(?&lt;=\w)%s\b(?!\w)'%TEXTO</code>
I find it's useful when you can't use <code>{}</code> for variable (here replaced with <code>%s</code>)

I'd like to use a <code>variable</code> inside a <code>regex</code>, how can I do this in <code>Python</code>?

<pre><code>TEXTO = sys.argv[1]

if re.search(r"\b(?=\w)TEXTO\b(?!\w)", subject, re.IGNORECASE):
 # Successful match
else:
 # Match attempt failed
</code></pre>

How to use a variable inside a regular expression?

Python

我想在regex中使用variable，如何在Python中执行此操作TEXTO = sys.argv[1]if re.search(r"\b(?=\w)TEXTO\b(?!\w)", subject, re.IGNORECASE):    # Successful matchelse:    # Match attempt failed

问如何在正则表达式中使用变量？
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问如何在正则表达式中使用变量？
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