%s 在 python 格式字符串中是什么意思? [英] What does %s mean in a python format string?

问题描述

%s 在 Python 中是什么意思?下面这段代码有什么作用?

What does %s mean in Python? And what does the following bit of code do?

例如...

 if len(sys.argv) < 2:
     sys.exit('Usage: %s database-name' % sys.argv[0])

 if not os.path.exists(sys.argv[1]):
     sys.exit('ERROR: Database %s was not found!' % sys.argv[1])

推荐答案

它是一种字符串格式化语法(从 C 中借用).

It is a string formatting syntax (which it borrows from C).

请参阅"PyFormat":

Python 支持将值格式化为字符串.虽然这可以包括非常复杂的表达，最基本用法是将值插入到带有 %s 占位符的字符串.

Python supports formatting values into strings. Although this can include very complicated expressions, the most basic usage is to insert values into a string with the %s placeholder.

这是一个非常简单的例子:

Here is a really simple example:

#Python2
name = raw_input("who are you? ")
print "hello %s" % (name,)

#Python3+
name = input("who are you? ")
print("hello %s" % (name,))

%s 标记允许我插入(并可能格式化)一个字符串.请注意，%s 标记被我在 % 符号之后传递给字符串的任何内容替换.另请注意，我在这里也使用了元组(当您只有一个字符串时，使用元组是可选的)来说明可以在一个语句中插入和格式化多个字符串.

The %s token allows me to insert (and potentially format) a string. Notice that the %s token is replaced by whatever I pass to the string after the % symbol. Notice also that I am using a tuple here as well (when you only have one string using a tuple is optional) to illustrate that multiple strings can be inserted and formatted in one statement.

这篇关于%s 在 python 格式字符串中是什么意思?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！