知识问答

如何在Python字符串中有选择地转义百分比（％）？

内容 隐藏
问题：如何在Python字符串中有选择地转义百分比（％）？
回答 0
回答 1
回答 2
回答 3
回答 4
回答 5
回答 6

问题：如何在Python字符串中有选择地转义百分比（％）？

我有以下代码

test = "have it break."
selectiveEscape = "Print percent % in sentence and not %s" % test

print(selectiveEscape)

我想获得输出：

Print percent % in sentence and not have it break.

实际发生的情况：

    selectiveEscape = "Use percent % in sentence and not %s" % test
TypeError: %d format: a number is required, not str
点击查看英文原文

I have the following code

test = "have it break."
selectiveEscape = "Print percent % in sentence and not %s" % test

print(selectiveEscape)

I would like to get the output:

Print percent % in sentence and not have it break.

What actually happens:

    selectiveEscape = "Use percent % in sentence and not %s" % test
TypeError: %d format: a number is required, not str

回答 0

>>> test = "have it break."
>>> selectiveEscape = "Print percent %% in sentence and not %s" % test
>>> print selectiveEscape
Print percent % in sentence and not have it break.
点击查看英文原文 
>>> test = "have it break."
>>> selectiveEscape = "Print percent %% in sentence and not %s" % test
>>> print selectiveEscape
Print percent % in sentence and not have it break.

回答 1

另外，从Python 2.6开始，您可以使用新的字符串格式（如PEP 3101中所述）：

'Print percent % in sentence and not {0}'.format(test)

当您的弦变得越来越复杂时，这尤其方便。

点击查看英文原文

Alternatively, as of Python 2.6, you can use new string formatting (described in PEP 3101):

'Print percent % in sentence and not {0}'.format(test)

which is especially handy as your strings get more complicated.

回答 2

尝试使用%%打印％符号。

点击查看英文原文

try using %% to print % sign .

回答 3

您不能选择性地转义%，因为%根据以下字符，它总是具有特殊的含义。

在Python 文档中，该部分第二个表格的底部指出：

'%'        No argument is converted, results in a '%' character in the result.

因此，您应该使用：

selectiveEscape = "Print percent %% in sentence and not %s" % (test, )

（请注意，将元组的显式更改作为的参数%）

在不了解上述情况的情况下，我会这样做：

selectiveEscape = "Print percent %s in sentence and not %s" % ('%', test)

显然你已经有了知识。

点击查看英文原文

You can’t selectively escape %, as % always has a special meaning depending on the following character.

In the documentation of Python, at the bottem of the second table in that section, it states:

'%'        No argument is converted, results in a '%' character in the result.

Therefore you should use:

selectiveEscape = "Print percent %% in sentence and not %s" % (test, )

(please note the expicit change to tuple as argument to %)

Without knowing about the above, I would have done:

selectiveEscape = "Print percent %s in sentence and not %s" % ('%', test)

with the knowledge you obviously already had.

回答 4

如果从文件中读取了格式模板，并且不能确保内容将百分号加倍，则可能必须检测百分号并以编程方式确定它是否是占位符的开始。然后，解析器还应该识别类似%d（以及可以使用的其他字母）之类的序列，也应如此%(xxx)s。

使用新格式可以观察到类似的问题-文本可以包含花括号。

点击查看英文原文

If the formatting template was read from a file, and you cannot ensure the content doubles the percent sign, then you probably have to detect the percent character and decide programmatically whether it is the start of a placeholder or not. Then the parser should also recognize sequences like %d (and other letters that can be used), but also %(xxx)s etc.

Similar problem can be observed with the new formats — the text can contain curly braces.

回答 5

如果您使用的是Python 3.6或更高版本，则可以使用f-string：

>>> test = "have it break."
>>> selectiveEscape = f"Print percent % in sentence and not {test}"
>>> print(selectiveEscape)
... Print percent % in sentence and not have it break.
点击查看英文原文

If you are using Python 3.6 or newer, you can use f-string:

>>> test = "have it break."
>>> selectiveEscape = f"Print percent % in sentence and not {test}"
>>> print(selectiveEscape)
... Print percent % in sentence and not have it break.

回答 6

我尝试了不同的方法来打印子图标题，看看它们是如何工作的。当我使用乳胶时，情况有所不同。

在典型情况下，它适用于’%%’和’string’+’％’。

如果您使用Latex，则可以使用’string’+’\％’

因此，在典型情况下：

import matplotlib.pyplot as plt
fig,ax = plt.subplots(4,1)
float_number = 4.17
ax[0].set_title('Total: (%1.2f' %float_number + '\%)')
ax[1].set_title('Total: (%1.2f%%)' %float_number)
ax[2].set_title('Total: (%1.2f' %float_number + '%%)')
ax[3].set_title('Total: (%1.2f' %float_number + '%)')

带有％的标题示例

如果我们使用乳胶：

import matplotlib.pyplot as plt
import matplotlib
font = {'family' : 'normal',
        'weight' : 'bold',
        'size'   : 12}
matplotlib.rc('font', **font)
matplotlib.rcParams['text.usetex'] = True
matplotlib.rcParams['text.latex.unicode'] = True
fig,ax = plt.subplots(4,1)
float_number = 4.17
#ax[0].set_title('Total: (%1.2f\%)' %float_number) This makes python crash
ax[1].set_title('Total: (%1.2f%%)' %float_number)
ax[2].set_title('Total: (%1.2f' %float_number + '%%)')
ax[3].set_title('Total: (%1.2f' %float_number + '\%)')

我们得到这样的结果： 具有％和乳胶的标题示例

点击查看英文原文

I have tried different methods to print a subplot title, look how they work. It’s different when i use Latex.

It works with ‘%%’ and ‘string’+’%’ in a typical case.

If you use Latex it worked using ‘string’+’\%’

So in a typical case:

import matplotlib.pyplot as plt
fig,ax = plt.subplots(4,1)
float_number = 4.17
ax[0].set_title('Total: (%1.2f' %float_number + '\%)')
ax[1].set_title('Total: (%1.2f%%)' %float_number)
ax[2].set_title('Total: (%1.2f' %float_number + '%%)')
ax[3].set_title('Total: (%1.2f' %float_number + '%)')

Title examples with %

If we use latex:

import matplotlib.pyplot as plt
import matplotlib
font = {'family' : 'normal',
        'weight' : 'bold',
        'size'   : 12}
matplotlib.rc('font', **font)
matplotlib.rcParams['text.usetex'] = True
matplotlib.rcParams['text.latex.unicode'] = True
fig,ax = plt.subplots(4,1)
float_number = 4.17
#ax[0].set_title('Total: (%1.2f\%)' %float_number) This makes python crash
ax[1].set_title('Total: (%1.2f%%)' %float_number)
ax[2].set_title('Total: (%1.2f' %float_number + '%%)')
ax[3].set_title('Total: (%1.2f' %float_number + '\%)')

We get this: Title example with % and latex