Python 字符串格式中的 %s 和 %d 有什么区别？

What's the difference between %s and %d in Python string formatting?

提问by karlzt

I don't understand what %sand %ddo and how they work.

我不明白它们是什么%s、%d做什么以及它们是如何工作的。

回答by moinudin

They are used for formatting strings. %sacts a placeholder for a string while %dacts as a placeholder for a number. Their associated values are passed in via a tuple using the %operator.

它们用于格式化字符串。%s充当字符串的占位符，同时%d充当数字的占位符。它们的关联值使用%运算符通过元组传入。

name = 'marcog'
number = 42
print '%s %d' % (name, number)

will print marcog 42. Note that name is a string (%s) and number is an integer (%d for decimal).

将打印marcog 42。请注意，name 是一个字符串 (%s)，而 number 是一个整数（%d 表示十进制）。

See https://docs.python.org/3/library/stdtypes.html#printf-style-string-formattingfor details.

有关详细信息，请参阅https://docs.python.org/3/library/stdtypes.html#printf-style-string-formatting。

In Python 3 the example would be:

在 Python 3 中，示例是：

print('%s %d' % (name, number))

回答by Lucas Jones

They are format specifiers. They are used when you want to include the value of your Python expressions into strings, with a specific format enforced.

它们是格式说明符。当您想将 Python 表达式的值包含到字符串中时使用它们，并强制执行特定格式。

See Dive into Pythonfor a relatively detailed introduction.

比较详细的介绍见Dive into Python。

回答by Soviut

%sis used as a placeholder for string values you want to inject into a formatted string.

%s用作要注入格式化字符串的字符串值的占位符。

%dis used as a placeholder for numeric or decimal values.

%d用作数字或十进制值的占位符。

For example (for python 3)

例如（对于python 3）

print ('%s is %d years old' % ('Joe', 42))

Would output

会输出

Joe is 42 years old

回答by kevin

These are placeholders:

这些是占位符：

For example: 'Hi %s I have %d donuts' %('Alice', 42)

例如： 'Hi %s I have %d donuts' %('Alice', 42)

This line of code will substitute %s with Alice (str) and %d with 42.

这行代码将用 Alice (str) 替换 %s，用 42 替换 %d。

Output: 'Hi Alice I have 42 donuts'

输出： 'Hi Alice I have 42 donuts'

This could be achieved with a "+" most of the time. To gain a deeper understanding to your question, you may want to check {} / .format() as well. Here is one example: Python string formatting: % vs. .format

大多数情况下，这可以通过“+”来实现。为了更深入地了解您的问题，您可能还需要检查 {} / .format()。这是一个示例：Python 字符串格式：% vs. .format

also see here a google python tutorial video @ 40', it has some explanations https://www.youtube.com/watch?v=tKTZoB2Vjuk

也可以在这里看到一个 google python 教程视频@ 40'，它有一些解释 https://www.youtube.com/watch?v=tKTZoB2Vjuk

回答by Sujatha

In case you would like to avoid %s or %d then..

如果您想避免 %s 或 %d 那么..

name = 'marcog'
number = 42
print ('my name is',name,'and my age is:', number)

Output:

输出：

my name is marcog and my name is 42

回答by Leo

%dand %sare placeholders, they work as a replaceable variable. For example, if you create 2 variables

%d并且%s是占位符，它们用作可替换的变量。例如，如果您创建 2 个变量

variable_one = "Stackoverflow"
variable_two = 45

you can assign those variables to a sentence in a string using a tuple of the variables.

您可以使用变量元组将这些变量分配给字符串中的句子。

variable_3 = "I was searching for an answer in %s and found more than %d answers to my question"

Note that %sworks for String and %dwork for numerical or decimal variables.

请注意，它%s适用于 String 并%d适用于数字或十进制变量。

if you print variable_3it would look like this

如果你打印variable_3它看起来像这样

print(variable_3 % (variable_one, variable_two))

I was searching for an answer in StackOverflow and found more than 45 answers to my question.

我在 StackOverflow 中寻找答案，发现我的问题有超过 45 个答案。

回答by Stiffy2000

The %dand %sstring formatting "commands" are used to format strings. The %dis for numbers, and %sis for strings.

在%d与%s字符串格式化“命令”用于格式字符串。的%d是数字，%s是用于字符串。

For an example:

例如：

print("%s" % "hi")

and

和

print("%d" % 34.6)

To pass multiple arguments:

传递多个参数：

print("%s %s %s%d" % ("hi", "there", "user", 123456))will return hi there user123456

print("%s %s %s%d" % ("hi", "there", "user", 123456))将返回 hi there user123456

回答by venergiac

from python 3 doc

来自python 3 文档

%dis for decimal integer

%d是十进制整数

%sis for generic string or object and in case of object, it will be converted to string

%s用于通用字符串或对象，如果是对象，它将被转换为字符串

Consider the following code

考虑以下代码

name ='giacomo'
number = 4.3
print('%s %s %d %f %g' % (name, number, number, number, number))

the out put will be

输出将是

giacomo 4.3 4 4.300000 4.3

贾科莫 4.3 4 4.300000 4.3

as you can see %dwill truncate to integer, %swill maintain formatting, %fwill print as float and %gis used for generic number

如您所见，%d将截断为整数，%s将保持格式，%f将打印为浮点数并%g用于通用数字

obviously

明显地

print('%d' % (name))

will generate an exception; you cannot convert string to number

会产生异常；您不能将字符串转换为数字

回答by a_m_dev

speaking of which ...
python3.6 comes with f-stringswhich makes things much easier in formatting!
now if your python version is greater than 3.6 you can format your strings with these available methods:

说到这……
python3.6 自带的，f-strings这让格式化变得更容易了！
现在，如果您的 python 版本大于 3.6，您可以使用以下可用方法格式化字符串：

name = "python"

print ("i code with %s" %name)          # with help of older method
print ("i code with {0}".format(name))  # with help of format
print (f"i code with {name}")           # with help of f-strings

回答by Agnel Vishal

As per latest standards, this is how it should be done.

按照最新的标准，这应该是这样做的。

print("My name is {!s} and my number is{:d}".format("Agnel Vishal",100))

Do check python3.6 docsand sample program

检查python3.6 文档和示例程序