blocks|key|3683506|text|您需要将{{和}}增加一倍|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3683507|>>>+x+=+"+{{+Hello+}}+{0}+"
>>>+print(x.format(42))
'+{+Hello+}+42+'|code-block|syntax|javascript|3683508|下面是Python+documentation+for+format+string+syntax的相关部分|3683509|3683510|格式的字符串包含用大括号{}括起来的“替换字段”。任何未包含在大括号中的内容都被视为原文本，它会原封不动地复制到输出中。如果您需要在文字文本中包含一个大括号字符，可以通过双击{{和}}对其进行转义。|blockquote|3683511|3683512|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/library/string.html#formatstrings^0|4|2|7|2|0|0|3|19|0|0|0|C|2|2F|2|2I|2|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|14|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|15|8|@]|D|@$9|16|A|17|1|18]]|E|$]]|$1|M|3|-4|5|6|7|19|8|@]|D|@]|E|$]]|$1|N|3|O|5|P|7|1A|8|@$9|1B|A|1C|B|C]|$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|1H|8|@]|D|@]|E|$]]|$1|R|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]]|S|$T|$5|U|V|W|E|$X|Y]]]]

You need to double the <code>{{</code> and <code>}}</code>:

<pre><code>&gt;&gt;&gt; x = " {{ Hello }} {0} "
&gt;&gt;&gt; print(x.format(42))
' { Hello } 42 '
</code></pre>

Here's the relevant part of the <a href="https://docs.python.org/library/string.html#formatstrings" rel="noreferrer">Python documentation for format string syntax</a>:

<blockquote>
 Format strings contain “replacement fields” surrounded by curly braces <code>{}</code>. Anything that is not contained in braces is considered literal text, which is copied unchanged to the output. If you need to include a brace character in the literal text, it can be escaped by doubling: <code>{{</code> and <code>}}</code>.
</blockquote>

blocks|key|1613949|text|Python+3.6%2B+(2017)|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|1613950|在最近的Python版本中，可以使用f-strings+(也可以参见PEP498)。|1613951|对于f字符串，应该使用双{{或}}|CODE|1613952|n+=+42++
print(f"+{{Hello}}+{n}+")|code-block|syntax|javascript|1613953|生成所需的|1613954|+{Hello}+42|1613955|如果需要在方括号中解析表达式，而不是使用文字文本，则需要三组方括号：|1613956|hello+=+"HELLO"
print(f"{{{hello.lower()}}}")|1613957|产生|1613958|{hello}|1613959|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/3/reference/lexical_analysis.html#f-strings|1|https://www.python.org/dev/peps/pep-0498/^0|0|I|0|I|9|0|Y|6|1|0|C|2|F|2|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1B|8|@$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1E|8|@]|D|@$9|1F|A|1G|1|1H]|$9|1I|A|1J|1|1K]]|E|$]]|$1|H|3|I|5|6|7|1L|8|@$9|1M|A|1N|B|J]|$9|1O|A|1P|B|J]]|D|@]|E|$]]|$1|K|3|L|5|M|7|1Q|8|@]|D|@]|E|$N|O]]|$1|P|3|Q|5|6|7|1R|8|@]|D|@]|E|$]]|$1|R|3|S|5|M|7|1S|8|@]|D|@]|E|$N|O]]|$1|T|3|U|5|6|7|1T|8|@]|D|@]|E|$]]|$1|V|3|W|5|M|7|1U|8|@]|D|@]|E|$N|O]]|$1|X|3|Y|5|6|7|1V|8|@]|D|@]|E|$]]|$1|Z|3|10|5|M|7|1W|8|@]|D|@]|E|$N|O]]|$1|11|3|-4|5|6|7|1X|8|@]|D|@]|E|$]]]|12|$13|$5|14|15|16|E|$17|18]]|19|$5|14|15|16|E|$17|1A]]]]

Python 3.6+ (2017)

In the recent versions of Python one would use <a href="https://docs.python.org/3/reference/lexical_analysis.html#f-strings" rel="noreferrer">f-strings</a> (see also <a href="https://www.python.org/dev/peps/pep-0498/" rel="noreferrer">PEP498</a>).

With f-strings one should use double <code>{{</code> or <code>}}</code>

<pre><code>n = 42 
print(f" {{Hello}} {n} ")
</code></pre>

produces the desired

<pre><code> {Hello} 42
</code></pre>

If you need to resolve an expression in the brackets instead of using literal text you'll need three sets of brackets:

<pre><code>hello = "HELLO"
print(f"{{{hello.lower()}}}")
</code></pre>

produces

<pre><code>{hello}
</code></pre>

blocks|key|2157762|text|您可以通过将大括号加倍来对其进行转义。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2157763|例如：|2157764|x+=+"{{+Hello+}}+{0}"
print(x.format(42))|code-block|syntax|javascript|2157765|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You escape it by doubling the braces.

Eg:

<pre><code>x = "{{ Hello }} {0}"
print(x.format(42))
</code></pre>

blocks|key|2161152|text|OP写了这样的评论：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2161153|出于某些目的，我尝试格式化一个小的|2161154|，例如：'{"all":+false,+"selected":+"{}"}'.format(data)以获得类似{"all":+false,+"selected":+"1,2"}的内容|blockquote|offset|length|style|CODE|2161155|2161156|2161157|在处理JSON时，出现“转义大括号”问题是很常见的。|2161158|我建议这样做：|2161159|import+json
data+=+"1,2"
mydict+=+{"all":+"false",+"selected":+data}
json.dumps(mydict)|code-block|syntax|javascript|2161160|它比另一种方法更干净，即：|2161161|'{{"all":+false,+"selected":+"{}"}}'.format(data)|2161162|当json字符串比示例更复杂时，使用JSON库无疑更可取。|2161163|entityMap^0|0|0|4|1B|1K|X|0|0|0|0|0|0|0|0|1|4|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|14|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|15|8|@$G|16|H|17|I|J]|$G|18|H|19|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1C|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1D|8|@]|9|@]|A|$]]|$1|Q|3|R|5|S|7|1E|8|@]|9|@]|A|$T|U]]|$1|V|3|W|5|6|7|1F|8|@]|9|@]|A|$]]|$1|X|3|Y|5|S|7|1G|8|@]|9|@]|A|$T|U]]|$1|Z|3|10|5|6|7|1H|8|@$G|1I|H|1J|I|J]]|9|@]|A|$]]|$1|11|3|-4|5|6|7|1K|8|@]|9|@]|A|$]]]|12|$]]

The OP wrote this comment:

<blockquote>
 I was trying to format a small JSON for some purposes, like this: <code>'{"all": false, "selected": "{}"}'.format(data)</code> to get something like <code>{"all": false, "selected": "1,2"}</code>
</blockquote>

It's pretty common that the "escaping braces" issue comes up when dealing with JSON.

I suggest doing this:

<pre><code>import json
data = "1,2"
mydict = {"all": "false", "selected": data}
json.dumps(mydict)
</code></pre>

It's cleaner than the alternative, which is:

<pre><code>'{{"all": false, "selected": "{}"}}'.format(data)
</code></pre>

Using the <code>json</code> library is definitely preferable when the JSON string gets more complicated than the example.

blocks|key|2157754|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2157755|x+=+"{{+Hello+}}+{0}"|offset|length|style|CODE|2157756|entityMap^0|0|0|L|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Try this:

<code>x = "{{ Hello }} {0}"</code>

blocks|key|2157767|text|试着这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2157768|x+=+"+{{+Hello+}}+{0}+"
print+x.format(42)|code-block|syntax|javascript|2157769|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|$]]

Try doing this:

<pre><code>x = " {{ Hello }} {0} "
print x.format(42)
</code></pre>

blocks|key|5281471|text|您希望使用字符{或}设置字符串的格式|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5281472|你只要把它们加倍就行了。|5281473|用f'{{'格式化{，用f'}}'格式化}|5281474|所以：|5281475|name+=+"bob"
print(f'Hello+{name}+!+I+want+to+print+}}+and+{{')|code-block|syntax|javascript|5281476|输出：|5281477|5281478|你好，鲍勃！我要打印}和{|blockquote|5281479|5281480|entityMap^0|7|1|9|1|0|0|1|5|9|1|C|5|K|1|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|14|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]|$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|1E|8|@]|D|@]|E|$]]|$1|L|3|M|5|N|7|1F|8|@]|D|@]|E|$O|P]]|$1|Q|3|R|5|6|7|1G|8|@]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1H|8|@]|D|@]|E|$]]|$1|T|3|U|5|V|7|1I|8|@]|D|@]|E|$]]|$1|W|3|-4|5|6|7|1J|8|@]|D|@]|E|$]]|$1|X|3|-4|5|6|7|1K|8|@]|D|@]|E|$]]]|Y|$]]

You want to format a string with the character <code>{</code> or <code>}</code>
You just have to double them.
format <code>{</code> with <code>f'{{'</code> and <code>}</code>with <code>f'}}'</code>
So :
<pre><code>name = &quot;bob&quot;
print(f'Hello {name} ! I want to print }} and {{')
</code></pre>
Output :
<blockquote>
Hello bob ! I want to print } and {
</blockquote>

blocks|key|5280772|text|尽管不是更好，但仅供参考，您也可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5280773|>>>+x+=+'{}Hello{}+{}'
>>>+print+x.format('{','}',42)
{Hello}+42|code-block|syntax|javascript|5280774|例如，当有人想要打印{argument}时，它可能很有用。它可能比'{{{}}}'.format('argument')更具可读性|offset|length|style|CODE|5280775|请注意，在Python2.7之后省略了参数位置(例如{}而不是{0}|5280776|entityMap^0|0|0|A|A|X|R|0|Q|2|V|3|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]|$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@$I|Y|J|Z|K|L]|$I|10|J|11|K|L]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|P|$]]

Although not any better, just for the reference, you can also do this:

<pre><code>&gt;&gt;&gt; x = '{}Hello{} {}'
&gt;&gt;&gt; print x.format('{','}',42)
{Hello} 42
</code></pre>

It can be useful for example when someone wants to print <code>{argument}</code>. It is maybe more readable than <code>'{{{}}}'.format('argument')</code>

Note that you omit argument positions (e.g. <code>{}</code> instead of <code>{0}</code>) after Python 2.7

blocks|key|2161239|text|如果您需要在字符串中保留两个大括号，则需要在变量的两边各使用5个大括号。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2161240|>>>+myvar+=+'test'
>>>+"{{{{{0}}}}}".format(myvar)
'{{test}}'|code-block|syntax|javascript|2161241|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|$]]

If you need to keep two curly braces in the string, you need 5 curly braces on each side of the variable.

<pre><code>&gt;&gt;&gt; myvar = 'test'
&gt;&gt;&gt; "{{{{{0}}}}}".format(myvar)
'{{test}}'
</code></pre>

blocks|key|1613894|text|如果您要经常这样做，那么最好定义一个实用函数，让您使用任意的花括号替代，例如|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1613895|def+custom_format(string,+brackets,+*args,+**kwargs):
++++if+len(brackets)+!=+2:
++++++++raise+ValueError('Expected+two+brackets.+Got+{}.'.format(len(brackets)))
++++padded+=+string.replace('{',+'{{').replace('}',+'}}')
++++substituted+=+padded.replace(brackets[0],+'{').replace(brackets[1],+'}')
++++formatted+=+substituted.format(*args,+**kwargs)
++++return+formatted

>>>+custom_format('{{[cmd]}+process+1}',+brackets='[]',+cmd='firefox.exe')
'{{firefox.exe}+process+1}'|code-block|syntax|javascript|1613896|请注意，这将适用于括号长度为2的字符串或可迭代的两个字符串(用于多字符分隔符)。|1613897|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

If you are going to be doing this a lot, it might be good to define a utility function that will let you use arbitrary brace substitutes instead, like

<pre><code>def custom_format(string, brackets, *args, **kwargs):
 if len(brackets) != 2:
 raise ValueError('Expected two brackets. Got {}.'.format(len(brackets)))
 padded = string.replace('{', '{{').replace('}', '}}')
 substituted = padded.replace(brackets[0], '{').replace(brackets[1], '}')
 formatted = substituted.format(*args, **kwargs)
 return formatted

&gt;&gt;&gt; custom_format('{{[cmd]} process 1}', brackets='[]', cmd='firefox.exe')
'{{firefox.exe} process 1}'
</code></pre>

Note that this will work either with brackets being a string of length 2 or an iterable of two strings (for multi-character delimiters).

blocks|key|1614100|text|我最近遇到了这个问题，因为我想将字符串注入到预先格式化的JSON中。我的解决方案是创建一个助手方法，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1614101|def+preformat(msg):
++++"""+allow+{{key}}+to+be+used+for+formatting+in+text
++++that+already+uses+curly+braces.++First+switch+this+into
++++something+else,+replace+curlies+with+double+curlies,+and+then
++++switch+back+to+regular+braces
++++"""
++++msg+=+msg.replace('{{',+'<<<').replace('}}',+'>>>')
++++msg+=+msg.replace('{',+'{{').replace('}',+'}}')
++++msg+=+msg.replace('<<<',+'{').replace('>>>',+'}')
++++return+msg|code-block|syntax|javascript|1614102|然后，您可以执行以下操作：|1614103|formatted+=+preformat("""
++++{
++++++++"foo":+"{{bar}}"
++++}""").format(bar="gas")|1614104|在性能不成问题的情况下完成工作。|1614105|entityMap^0|0|0|0|0|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]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I recently ran into this, because I wanted to inject strings into preformatted JSON.
My solution was to create a helper method, like this:

<pre><code>def preformat(msg):
 """ allow {{key}} to be used for formatting in text
 that already uses curly braces. First switch this into
 something else, replace curlies with double curlies, and then
 switch back to regular braces
 """
 msg = msg.replace('{{', '&lt;&lt;&lt;').replace('}}', '&gt;&gt;&gt;')
 msg = msg.replace('{', '{{').replace('}', '}}')
 msg = msg.replace('&lt;&lt;&lt;', '{').replace('&gt;&gt;&gt;', '}')
 return msg
</code></pre>

You can then do something like:

<pre><code>formatted = preformat("""
 {
 "foo": "{{bar}}"
 }""").format(bar="gas")
</code></pre>

Gets the job done if performance is not an issue.

blocks|key|2161464|text|key+=+"FOOBAR"
print(f"hello+{{{key}}}")|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2161465|输出|unstyled|2161466|hello+{FOOBAR}|2161467|以防有人想要使用fstring在花括号内打印内容。|2161468|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$B|C]]|$1|I|3|J|5|F|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>key = &quot;FOOBAR&quot;
print(f&quot;hello {{{key}}}&quot;)
</code></pre>
outputs
<pre><code>hello {FOOBAR}
</code></pre>
In case someone wanted to print something inside curly brackets using fstrings.

blocks|key|2161350|text|我参加这个聚会要迟到得离谱。我成功地将括号放置在替换元素中，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2161351|print('{0}+{1}'.format('{hello}',+'{world}'))|code-block|syntax|javascript|2161352|哪种打印|2161353|{hello}+{world}|2161354|严格地说，这不是OP所要求的，因为s/他想要格式字符串中的大括号，但这可能会对某些人有所帮助。|2161355|entityMap^0|0|0|0|0|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]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I am ridiculously late to this party. I am having success placing the brackets in the replacement element, like this:
<pre><code>print('{0} {1}'.format('{hello}', '{world}'))
</code></pre>
which prints
<pre><code>{hello} {world}
</code></pre>
Strictly speaking this is not what OP is asking, as s/he wants the braces in the format string, but this may help someone.

blocks|key|3684874|text|我使用了双{{+}}来防止fstring值注入，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3684875|例如，下面是我的Postgres+UPDATE语句，用于更新一个整数数组列，该列采用{}表达式来捕获数组，即：|3684876|端口=+'{100,200,300}‘|3684877|使用fstring+its，|3684878|ports+=+[1,2,3]

query+=+f"""
+++UPDATE+table+SET+ports+=+'{{{ports}}}'+WHERE+id+=+1
"""|code-block|syntax|javascript|3684879|实际查询语句将是，|3684880|UPDATE+table+SET+ports+=+'{1,2,3}'|3684881|哪个是有效的postgres+satement？|3684882|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|X|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|Y|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|Q|3|R|5|6|7|11|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

I used a double {{ }} to prevent fstring value injection,
for example, heres my Postgres UPDATE statement to update a integer array column that takes expression of {} to capture the array, ie:
ports = '{100,200,300}'
with fstrings its,
<pre><code>ports = [1,2,3]

query = f&quot;&quot;&quot;
 UPDATE table SET ports = '{{{ports}}}' WHERE id = 1
&quot;&quot;&quot;

</code></pre>
the actual query statement will be,
<pre><code>UPDATE table SET ports = '{1,2,3}'
</code></pre>
which is a valid postgres satement

blocks|key|3684902|text|如果只想打印花括号的一侧：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3684903|a=3
print(f'{"{"}{a}')
>>>+{3|code-block|syntax|javascript|3684904|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|$]]

If you want to print just one side of the curly brace:
<pre><code>a=3
print(f'{&quot;{&quot;}{a}')
&gt;&gt;&gt; {3
</code></pre>

blocks|key|5280905|text|原因是，{}是.format()的语法，所以在您的示例中，.format()无法识别{Hello}，因此它抛出了一个错误。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5280906|您可以使用双花括号{{}}来覆盖它。|5280907|x+=+"+{{+Hello+}}+{0}+"|code-block|syntax|javascript|5280908|或|5280909|尝试使用%25s进行文本格式设置，|5280910|x+=+"+{+Hello+}+%25s"
print+x%25(42)++|5280911|entityMap^0|4|2|7|9|T|9|16|7|0|0|0|0|4|2|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|13|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|15|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|16|8|@$9|17|A|18|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|J|7|19|8|@]|D|@]|E|$K|L]]|$1|S|3|-4|5|6|7|1A|8|@]|D|@]|E|$]]]|T|$]]

Reason is , <code>{}</code> is the syntax of <code>.format()</code> so in your case <code>.format()</code> doesn't recognize <code>{Hello}</code> so it threw an error.

you can override it by using double curly braces {{}}, 

<pre><code>x = " {{ Hello }} {0} "
</code></pre>

or 

try <code>%s</code> for text formatting,

<pre><code>x = " { Hello } %s"
print x%(42) 
</code></pre>

blocks|key|3684745|text|您可以使用“引号墙”将格式化字符串部分与常规字符串部分分开。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3684746|发自：|3684747|print(f"{Hello}+{42}")|code-block|syntax|javascript|3684748|至|3684749|print("{Hello}"f"+{42}")|3684750|3684751|一个更清楚的例子是|3684752|string+=+10
print(f"{string}+{word}")|3684753|输出：|3684754|NameError:+name+'word'+is+not+defined|3684755|现在，像这样添加报价墙：|3684756|string+=+10
print(f"{string}""+{word}")|3684757|3684758|10+{word}|3684759|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|16|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|17|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|18|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|19|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|1A|8|@]|9|@]|A|$]]|$1|P|3|Q|5|F|7|1B|8|@]|9|@]|A|$G|H]]|$1|R|3|S|5|6|7|1C|8|@]|9|@]|A|$]]|$1|T|3|U|5|F|7|1D|8|@]|9|@]|A|$G|H]]|$1|V|3|W|5|6|7|1E|8|@]|9|@]|A|$]]|$1|X|3|Y|5|F|7|1F|8|@]|9|@]|A|$G|H]]|$1|Z|3|S|5|6|7|1G|8|@]|9|@]|A|$]]|$1|10|3|11|5|F|7|1H|8|@]|9|@]|A|$G|H]]|$1|12|3|-4|5|6|7|1I|8|@]|9|@]|A|$]]]|13|$]]

You can use a &quot;quote wall&quot; to separate the formatted string part from the regular string part.
From:
<pre><code>print(f&quot;{Hello} {42}&quot;)
</code></pre>
to
<pre><code>print(&quot;{Hello}&quot;f&quot; {42}&quot;)
</code></pre>
<hr />
A clearer example would be
<pre><code>string = 10
print(f&quot;{string} {word}&quot;)
</code></pre>
Output:
<pre><code>NameError: name 'word' is not defined
</code></pre>
Now, add the quote wall like so:
<pre><code>string = 10
print(f&quot;{string}&quot;&quot; {word}&quot;)
</code></pre>
Output:
<pre><code>10 {word}
</code></pre>

blocks|key|5281038|text|我在尝试打印文本时遇到了这个问题，我可以将文本复制粘贴到Latex文档中。我在this+answer上进行了扩展，并使用了命名替换字段：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|5281039|假设您想要打印出多个变量的乘积，其索引如下|5281040|📷|atomic|5281041|，在Latex中应该是$A_{+0042+}*A_{+3141+}*A_{+2718+}*A_{+0042+}$，下面的代码使用命名字段来完成这项工作，以便对许多索引保持可读：|style|CODE|5281042|idx_mapping+=+{'i1':42,+'i2':3141,+'i3':2178+}
print('$A_{{+{i1:04d}+}}+*+A_{{+{i2:04d}+}}+*+A_{{+{i3:04d}+}}+*+A_{{+{i1:04d}+}}$'.format(**idx_mapping))|code-block|syntax|javascript|5281043|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/5466478/5105118|1|IMAGE|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/10eb5b6e18080ae9d14fd39a727cf172.gif|imageAlt^0|13|B|0|0|0|0|1|1|0|B|19|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@]|9|@$A|16|B|17|1|18]]|C|$]]|$1|D|3|E|5|6|7|19|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|1A|8|@]|9|@$A|1B|B|1C|1|1D]]|C|$]]|$1|I|3|J|5|6|7|1E|8|@$A|1F|B|1G|K|L]]|9|@]|C|$]]|$1|M|3|N|5|O|7|1H|8|@]|9|@]|C|$P|Q]]|$1|R|3|-4|5|6|7|1I|8|@]|9|@]|C|$]]]|S|$T|$5|U|V|W|C|$X|Y]]|Z|$5|10|V|11|C|$12|13|14|-4]]]]

I stumbled upon this problem when trying to print text, which I can copy paste into a Latex document. I extend on <a href="https://stackoverflow.com/a/5466478/5105118">this answer</a> and make use of named replacement fields:

Lets say you want to print out a product of mulitple variables with indices such as
<a href="https://i.stack.imgur.com/YQt0F.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YQt0F.gif" alt="enter image description here"></a>, which in Latex would be <code>$A_{ 0042 }*A_{ 3141 }*A_{ 2718 }*A_{ 0042 }$</code>
The following code does the job with named fields so that for many indices it stays readable:

<pre><code>idx_mapping = {'i1':42, 'i2':3141, 'i3':2178 }
print('$A_{{ {i1:04d} }} * A_{{ {i2:04d} }} * A_{{ {i3:04d} }} * A_{{ {i1:04d} }}$'.format(**idx_mapping))
</code></pre>

blocks|key|5281129|text|如果您只想打印一个花括号(例如{)，您可以使用{{，如果您愿意，您可以稍后在字符串中添加更多的花括号。例如：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|5281130|>>>+f'{{+there+is+a+curly+brace+on+the+left.+Oh,+and+1+%2B+1+is+{1+%2B+1}'
'{+there+is+a+curly+brace+on+the+left.+Oh,+and+1+%2B+1+is+2'|code-block|syntax|javascript|5281131|entityMap^0|F|1|N|2|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

If you want to only print one curly brace (for example <code>{</code>) you can use <code>{{</code>, and you can add more braces later in the string if you want. 
For example:

<pre><code>&gt;&gt;&gt; f'{{ there is a curly brace on the left. Oh, and 1 + 1 is {1 + 1}'
'{ there is a curly brace on the left. Oh, and 1 + 1 is 2'
</code></pre>

blocks|key|5281309|text|如果在可格式化的f-string模板中需要大括号，则需要输出一个字符串，该字符串包含f-+string的一组大括号中的两个大括号：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5281310|css_template+=+f"{{tag}}+{'{{'}+margin:+0;+padding:+0;{'}}'}"
for_p+=+css_template.format(tag="p")
#+'p+{+margin:+0;+padding:+0;}'|code-block|syntax|javascript|5281311|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|$]]

If you need curly braces within a f-string template that can be formatted, you need to output a string containing two curly braces within a set of curly braces for the f-string:
<pre class="lang-py prettyprint-override"><code>css_template = f&quot;{{tag}} {'{{'} margin: 0; padding: 0;{'}}'}&quot;
for_p = css_template.format(tag=&quot;p&quot;)
# 'p { margin: 0; padding: 0;}'
</code></pre>

blocks|key|2158086|text|或者只是对支架本身进行参数化？可能非常冗长。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2158087|x+=+'{open_bracket}42{close_bracket}'.format(open_bracket='{',+close_bracket='}')+
print(x)
#+{42}|code-block|syntax|javascript|2158088|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|$]]

Or just parametrize the bracket itself? Probably very verbose.
<pre><code>x = '{open_bracket}42{close_bracket}'.format(open_bracket='{', close_bracket='}') 
print(x)
# {42}
</code></pre>

blocks|key|1614173|text|当你只是尝试插入代码字符串时，我建议使用jinja2，这是一个功能齐全的Python模板引擎，例如：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1614174|from+jinja2+import+Template

foo+=+Template('''
#include+<stdio.h>

void+main()+{
++++printf("hello+universe+number+{{number}}");
}
''')

for+i+in+range(2):
++++print(foo.render(number=i))|code-block|syntax|javascript|1614175|因此，您不会像其他一堆答案所建议的那样，被迫复制大括号|1614176|entityMap|0|LINK|mutability|MUTABLE|url|https://palletsprojects.com/p/jinja/^0|K|6|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

When you're just trying to interpolate code strings I'd suggest using <a href="https://palletsprojects.com/p/jinja/" rel="nofollow noreferrer">jinja2</a> which is a full-featured template engine for Python, ie:

<pre><code>from jinja2 import Template

foo = Template('''
#include &lt;stdio.h&gt;

void main() {
 printf("hello universe number {{number}}");
}
''')

for i in range(2):
 print(foo.render(number=i))
</code></pre>

So you won't be enforced to duplicate curly braces as the whole bunch of other answers suggest

blocks|key|3684438|text|您可以使用原始字符串方法来完成此操作，只需在字符串前添加字符'r‘而不带引号。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3684439|#+to+print+'{I+am+inside+braces}'
print(r'{I+am+inside+braces}')|code-block|syntax|javascript|3684440|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 do this by using raw string method by simply adding character 'r' without quotes before the string.

<pre><code># to print '{I am inside braces}'
print(r'{I am inside braces}')
</code></pre>

blocks|key|5281174|text|使用转义序列转义f字符串中的花括号。例如:打印(f‘{a={1}}’)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5281175|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Use escape sequences to escape the curly braces in the f-string. Ex:print(f'{a={1}}')

<pre><code>x = " \{ Hello \} {0} "
print(x.format(42))
</code></pre>

gives me : <code>Key Error: Hello\\</code>

I want to print the output: <code>{Hello} 42</code>

How can I print literal curly-brace characters in a string and also use .format on it?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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x = " \{ Hello \} {0} "print(x.format(42))给我：Key Error: Hello\\我想打印输出：{Hello} 42

问如何在打印字符串中的文字大括号字符的同时对其使用.format？
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问如何在打印字符串中的文字大括号字符的同时对其使用.format？
EN