blocks|key|1330796|text|string类型不支持这一点。最好使用带有re.IGNORECASE选项的the+regular+expression+sub+method。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1330797|>>>+import+re
>>>+insensitive_hippo+=+re.compile(re.escape('hippo'),+re.IGNORECASE)
>>>+insensitive_hippo.sub('giraffe',+'I+want+a+hIPpo+for+my+birthday')
'I+want+a+giraffe+for+my+birthday'|code-block|syntax|javascript|1330798|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.python.org/library/re.html#re.IGNORECASE|1|https://docs.python.org/3/library/re.html#re.sub^0|0|6|L|D|0|11|X|1|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]|$9|10|A|11|1|12]]|E|$]]|$1|F|3|G|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]|S|$5|N|O|P|E|$Q|T]]]]

The <code>string</code> type doesn't support this. You're probably best off using <a href="https://docs.python.org/3/library/re.html#re.sub" rel="noreferrer">the regular expression sub method</a> with the <a href="http://docs.python.org/library/re.html#re.IGNORECASE" rel="noreferrer">re.IGNORECASE</a> option.
<pre><code>&gt;&gt;&gt; import re
&gt;&gt;&gt; insensitive_hippo = re.compile(re.escape('hippo'), re.IGNORECASE)
&gt;&gt;&gt; insensitive_hippo.sub('giraffe', 'I want a hIPpo for my birthday')
'I want a giraffe for my birthday'
</code></pre>

blocks|key|1546045|text|import+re
pattern+=+re.compile("hello",+re.IGNORECASE)
pattern.sub("bye",+"hello+HeLLo+HELLO")
#+'bye+bye+bye'|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1546046|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>import re
pattern = re.compile("hello", re.IGNORECASE)
pattern.sub("bye", "hello HeLLo HELLO")
# 'bye bye bye'
</code></pre>

blocks|key|1330871|text|在一行中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1330872|import+re
re.sub("(?i)hello","bye",+"hello+HeLLo+HELLO")+#'bye+bye+bye'
re.sub("(?i)he\.llo","bye",+"he.llo+He.LLo+HE.LLO")+#'bye+bye+bye'|code-block|syntax|javascript|1330873|或者，使用可选的“flag”参数：|1330874|import+re
re.sub("hello",+"bye",+"hello+HeLLo+HELLO",+flags=re.I)+#'bye+bye+bye'
re.sub("he\.llo",+"bye",+"he.llo+He.LLo+HE.LLO",+flags=re.I)+#'bye+bye+bye'|1330875|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|$]]

In a single line:

<pre><code>import re
re.sub("(?i)hello","bye", "hello HeLLo HELLO") #'bye bye bye'
re.sub("(?i)he\.llo","bye", "he.llo He.LLo HE.LLO") #'bye bye bye'
</code></pre>

Or, use the optional "flags" argument:

<pre><code>import re
re.sub("hello", "bye", "hello HeLLo HELLO", flags=re.I) #'bye bye bye'
re.sub("he\.llo", "bye", "he.llo He.LLo HE.LLO", flags=re.I) #'bye bye bye'
</code></pre>

blocks|key|1546079|text|继续bFloch的回答，这个函数将以不区分大小写的方式更改所有出现的old和new。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1546080|def+ireplace(old,+new,+text):
++++idx+=+0
++++while+idx+<+len(text):
++++++++index_l+=+text.lower().find(old.lower(),+idx)
++++++++if+index_l+==+-1:
++++++++++++return+text
++++++++text+=+text[:index_l]+%2B+new+%2B+text[index_l+%2B+len(old):]
++++++++idx+=+index_l+%2B+len(new)+
++++return+text|code-block|syntax|javascript|1546081|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|$]]

Continuing on bFloch's answer, this function will change not one, but all occurrences of old with new - in a case insensitive fashion. 

<pre><code>def ireplace(old, new, text):
 idx = 0
 while idx &lt; len(text):
 index_l = text.lower().find(old.lower(), idx)
 if index_l == -1:
 return text
 text = text[:index_l] + new + text[index_l + len(old):]
 idx = index_l + len(new) 
 return text
</code></pre>

blocks|key|1546142|text|像布莱尔一样，康拉德说string.replace不支持这一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1546143|使用正则表达式re.sub，但请记住首先对替换字符串进行转义。请注意，在2.6中没有针对re.sub的标志-选项，因此您必须使用嵌入式修饰符'(?i)'+(或RE对象，请参阅布莱尔·康拉德的答案)。此外，另一个缺陷是，如果给出了一个字符串，sub将在替换文本中处理反斜杠转义。为了避免这种情况，可以传入一个lambda。|offset|length|style|CODE|1546144|下面是一个函数：|1546145|import+re
def+ireplace(old,+repl,+text):
++++return+re.sub('(?i)'%2Bre.escape(old),+lambda+m:+repl,+text)

>>>+ireplace('hippo?',+'giraffe!?',+'You+want+a+hiPPO?')
'You+want+a+giraffe!?'
>>>+ireplace(r'[binfolder]',+r'C:\Temp\bin',+r'[BinFolder]\test.exe')
'C:\\Temp\\bin\\test.exe'|code-block|syntax|javascript|1546146|entityMap^0|0|7|6|18|6|1Y|6|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]|$D|U|E|V|F|G]|$D|W|E|X|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|Y|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|Z|8|@]|9|@]|A|$M|N]]|$1|O|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|P|$]]

Like Blair Conrad says string.replace doesn't support this.

Use the regex <code>re.sub</code>, but remember to escape the replacement string first. Note that there's no flags-option in 2.6 for <code>re.sub</code>, so you'll have to use the embedded modifier <code>'(?i)'</code> (or a RE-object, see Blair Conrad's answer). Also, another pitfall is that sub will process backslash escapes in the replacement text, if a string is given. To avoid this one can instead pass in a lambda.

Here's a function:

<pre><code>import re
def ireplace(old, repl, text):
 return re.sub('(?i)'+re.escape(old), lambda m: repl, text)

&gt;&gt;&gt; ireplace('hippo?', 'giraffe!?', 'You want a hiPPO?')
'You want a giraffe!?'
&gt;&gt;&gt; ireplace(r'[binfolder]', r'C:\Temp\bin', r'[BinFolder]\test.exe')
'C:\\Temp\\bin\\test.exe'
</code></pre>

blocks|key|1330953|text|此函数同时使用str.replace()和re.findall()函数。它将以不区分大小写的方式将string中所有出现的pattern替换为repl。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1330954|def+replace_all(pattern,+repl,+string)+->+str:
+++occurences+=+re.findall(pattern,+string,+re.IGNORECASE)
+++for+occurence+in+occurences:
+++++++string+=+string.replace(occurence,+repl)
+++++++return+string|code-block|syntax|javascript|1330955|entityMap^0|7|D|L|C|1D|6|1P|7|1Z|4|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|L|$]]

This function uses both the <code>str.replace()</code> and <code>re.findall()</code> functions.
It will replace all occurences of <code>pattern</code> in <code>string</code> with <code>repl</code> in a case-insensitive way.

<pre><code>def replace_all(pattern, repl, string) -&gt; str:
 occurences = re.findall(pattern, string, re.IGNORECASE)
 for occurence in occurences:
 string = string.replace(occurence, repl)
 return string
</code></pre>

blocks|key|1546273|text|关于语法细节和选项的有趣观察：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1546274|win32上的Python+3.7.2+(tags/v3.7.2:9a3ffc0492，Dec+23，23:09:28)+MSC+v.1916+64位(AMD64)|1546275|import+re
old+=+"TREEROOT+treeroot+TREerOot"
re.sub(r'(?i)treeroot',+'grassroot',+old)|code-block|syntax|javascript|1546276|‘草根草根’|1546277|re.sub(r'treeroot',+'grassroot',+old)|1546278|‘树草根TREerOot’|1546279|re.sub(r'treeroot',+'grassroot',+old,+flags=re.I)|1546280|1546281|re.sub(r'treeroot',+'grassroot',+old,+re.I)|1546282|1546283|因此，匹配表达式中的(?i)前缀或添加"flags=re.I“作为第四个参数将导致不区分大小写的匹配。但是，仅使用"re.I“作为第四个参数并不会导致不区分大小写的匹配。|1546284|为了进行比较，|1546285|re.findall(r'treeroot',+old,+re.I)|1546286|‘树’，‘树’，'TREEROOT‘|1546287|re.findall(r'treeroot',+old)|1546288|“树根”|1546289|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|18|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|19|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|1A|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|1B|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|1C|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|1D|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|1E|8|@]|9|@]|A|$G|H]]|$1|Q|3|J|5|6|7|1F|8|@]|9|@]|A|$]]|$1|R|3|S|5|F|7|1G|8|@]|9|@]|A|$G|H]]|$1|T|3|N|5|6|7|1H|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1I|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1J|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|F|7|1K|8|@]|9|@]|A|$G|H]]|$1|10|3|11|5|6|7|1L|8|@]|9|@]|A|$]]|$1|12|3|13|5|F|7|1M|8|@]|9|@]|A|$G|H]]|$1|14|3|15|5|6|7|1N|8|@]|9|@]|A|$]]|$1|16|3|-4|5|6|7|1O|8|@]|9|@]|A|$]]]|17|$]]

An interesting observation about syntax details and options:

Python 3.7.2 (tags/v3.7.2:9a3ffc0492, Dec 23 2018, 23:09:28) [MSC v.1916 64 bit (AMD64)] on win32

<pre><code>import re
old = "TREEROOT treeroot TREerOot"
re.sub(r'(?i)treeroot', 'grassroot', old)
</code></pre>

'grassroot grassroot grassroot'

<pre><code>re.sub(r'treeroot', 'grassroot', old)
</code></pre>

'TREEROOT grassroot TREerOot'

<pre><code>re.sub(r'treeroot', 'grassroot', old, flags=re.I)
</code></pre>

'grassroot grassroot grassroot'

<pre><code>re.sub(r'treeroot', 'grassroot', old, re.I)
</code></pre>

'TREEROOT grassroot TREerOot'

So the (?i) prefix in the match expression or adding "flags=re.I" as a fourth argument will result in a case-insensitive match.
BUT, using just "re.I" as the fourth argument does not result in case-insensitive match. 

For comparison, 

<pre><code>re.findall(r'treeroot', old, re.I)
</code></pre>

['TREEROOT', 'treeroot', 'TREerOot']

<pre><code>re.findall(r'treeroot', old)
</code></pre>

['treeroot']

blocks|key|1546055|text|这不需要RegularExp|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1546056|def+ireplace(old,+new,+text):
++++"""+
++++Replace+case+insensitive
++++Raises+ValueError+if+string+not+found
++++"""
++++index_l+=+text.lower().index(old.lower())
++++return+text[:index_l]+%2B+new+%2B+text[index_l+%2B+len(old):]+|code-block|syntax|javascript|1546057|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|$]]

This doesn't require RegularExp

<pre><code>def ireplace(old, new, text):
 """ 
 Replace case insensitive
 Raises ValueError if string not found
 """
 index_l = text.lower().index(old.lower())
 return text[:index_l] + new + text[index_l + len(old):] 
</code></pre>

blocks|key|1546178|text|我将\t转换为escape+sequences+(向下滚动一点)，所以我注意到re.sub将带反斜杠的转义字符转换为转义序列。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1546179|为了防止这种情况，我写了以下内容：|1546180|替换不区分大小写。|1546181|import+re
++++def+ireplace(findtxt,+replacetxt,+data):
++++++++return+replacetxt.join(++re.compile(findtxt,+flags=re.I).split(data)++)|code-block|syntax|javascript|1546182|此外，如果你想用转义字符替换它，就像这里的其他答案一样，将特殊含义的斜杠字符转换为转义序列，只需解码find+and，或替换字符串。在python3中，可能需要执行类似.decode("unicode_escape")+#python3的操作|1546183|findtxt+=+findtxt.decode('string_escape')+#+python2
replacetxt+=+replacetxt.decode('string_escape')+#+python2
data+=+ireplace(findtxt,+replacetxt,+data)|1546184|在Python+2.7.8中测试|1546185|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/2/reference/lexical_analysis.html#string-literals|1|https://docs.python.org/2/library/re.html#re.sub^0|7|G|0|13|6|1|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@$A|13|B|14|1|15]|$A|16|B|17|1|18]]|C|$]]|$1|D|3|E|5|6|7|19|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|1A|8|@]|9|@]|C|$]]|$1|H|3|I|5|J|7|1B|8|@]|9|@]|C|$K|L]]|$1|M|3|N|5|6|7|1C|8|@]|9|@]|C|$]]|$1|O|3|P|5|J|7|1D|8|@]|9|@]|C|$K|L]]|$1|Q|3|R|5|6|7|1E|8|@]|9|@]|C|$]]|$1|S|3|-4|5|6|7|1F|8|@]|9|@]|C|$]]]|T|$U|$5|V|W|X|C|$Y|Z]]|10|$5|V|W|X|C|$Y|11]]]]

I was having \t being converted to the <a href="https://docs.python.org/2/reference/lexical_analysis.html#string-literals" rel="nofollow noreferrer">escape sequences</a> (scroll a bit down), so I noted that <a href="https://docs.python.org/2/library/re.html#re.sub" rel="nofollow noreferrer">re.sub</a> converts backslashed escaped characters to escape sequences.
To prevent that I wrote the following:
Replace case insensitive.
<pre><code>import re
 def ireplace(findtxt, replacetxt, data):
 return replacetxt.join( re.compile(findtxt, flags=re.I).split(data) )
</code></pre>
Also, if you want it to replace with the escape characters, like the other answers here that are getting the special meaning bashslash characters converted to escape sequences, just decode your find and, or replace string. In Python 3, might have to do something like .decode(&quot;unicode_escape&quot;) # python3
<pre><code>findtxt = findtxt.decode('string_escape') # python2
replacetxt = replacetxt.decode('string_escape') # python2
data = ireplace(findtxt, replacetxt, data)
</code></pre>
Tested in Python 2.7.8

blocks|key|1546091|text|i='I+want+a+hIPpo+for+my+birthday'
key='hippo'
swp='giraffe'

o=(i.lower().split(key))
c=0
p=0
for+w+in+o:
++++o[c]=i[p:p%2Blen(w)]
++++p=p%2Blen(key%2Bw)
++++c%2B=1
print(swp.join(o))|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1546092|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>i='I want a hIPpo for my birthday'
key='hippo'
swp='giraffe'

o=(i.lower().split(key))
c=0
p=0
for w in o:
 o[c]=i[p:p+len(w)]
 p=p+len(key+w)
 c+=1
print(swp.join(o))
</code></pre>

What's the easiest way to do a case-insensitive string replacement in Python?

Case insensitive replace

Python

在Python中进行不区分大小写的字符串替换最简单的方法是什么？

问不区分大小写的替换
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