在多行中连接python中的字符串

Concatenate strings in python in multiline

提问by user3290349

I have some strings to be concatenate and the resultant string will be quite long. I also have some variables to be concatenated.

我有一些字符串要连接，结果字符串会很长。我还有一些要连接的变量。

How can I combine both strings and variables so the result would be a multi line string?

如何组合字符串和变量，以便结果是多行字符串？

The following code throws error.

以下代码抛出错误。

str = "This is a line" +
       str1 +
       "This is line 2" +
       str2 +
       "This is line 3" ;

I have tried this too

我也试过这个

str = "This is a line" \
      str1 \
      "This is line 2" \
      str2 \
      "This is line 3" ;

Please suggest a way to do this.

请提出一种方法来做到这一点。

采纳答案by Bryan Oakley

There are several ways. A simple solution is to add parenthesis:

有几种方法。一个简单的解决方案是添加括号：

strz = ("This is a line" +
       str1 +
       "This is line 2" +
       str2 +
       "This is line 3")

If you want each "line" on a separate line you can add newline characters:

如果您希望每个“行”在单独的行上，您可以添加换行符：

strz = ("This is a line\n" +
       str1 + "\n" +
       "This is line 2\n" +
       str2 + "\n" +
       "This is line 3\n")

回答by Du?an Ma?ar

I would add everything I need to concatenate to a list and then join it on a line break.

我会添加我需要连接到列表的所有内容，然后在换行符处加入它。

my_str = '\n'.join(['string1', variable1, 'string2', variable2])

回答by Diogo Martins

Python isn't php and you have no need to put $before a variable name.

Python 不是 php，您无需$在变量名之前放置。

a_str = """This is a line
       {str1}
       This is line 2
       {str2}
       This is line 3""".format(str1="blabla", str2="blablabla2")

回答by winklerrr

Solutions for Python 3 using Formatted Strings

使用格式化字符串的 Python 3 解决方案

As of Python 3.6you can use so called "formatted strings" (or "f strings") to easily insert variables into your strings. Just add an fin front of the string and write the variable inside curly braces ({}) like so:

从Python 3.6 开始，您可以使用所谓的“格式化字符串”（或“f 字符串”）轻松地将变量插入到您的字符串中。只需f在字符串前面添加一个并将变量写入大括号 ( {}) 中，如下所示：

>>> name = "John Doe"
>>> f"Hello {name}"
'Hello John Doe'

To split a long string to multiple lines surround the parts with parentheses(()) or use a multi-line string(a string surrounded by three quotes """or '''instead of one).

要将长字符串拆分为多行，请使用括号( ()) 或使用多行字符串（由三个引号"""或'''代替一个引号包围的部分）。

1. Solution: Parentheses

1. 解决方案：括号

With parentheses around your strings you can even concatenate them without the need of a +sign in between:

在字符串周围加上括号，您甚至可以将它们连接起来，而无需在它们+之间添加符号：

a_str = (f"This is a line \n{str1}\n"
         f"This is line 2 \n{str2}\n"
         "This is line 3") # no variable here, so no leading f

Good to know:If there is no variable in a line, there is no need for a leading ffor that line.

很高兴知道：如果一行中没有变量，则该行不需要前导f。

Good to know:You could archive the same result with backslashes (\) at the end of each line instead of surrounding parentheses but accordingly to PEP8you should prefer parentheses for line continuation:

很高兴知道：您可以\在每行末尾使用反斜杠 ( ) 而不是环绕括号来存档相同的结果，但因此，对于PEP8，您应该更喜欢使用括号作为行的延续：

Long lines can be broken over multiple lines by wrapping expressions in parentheses. These should be used in preference to using a backslash for line continuation.

通过将表达式括在括号中，可以将长行分成多行。这些应该优先于使用反斜杠进行行延续。

2. Solution: Multi-Line String

2. 解决方案：多行字符串

In multi-line strings you don't need to explicitly insert \n, Python takes care of that for you:

在不需要显式插入的多行字符串中\n，Python 会为您处理：

a_str = f"""This is a line
        {str1}
        This is line 2
        {str2}
        This is line 3"""

Good to know:Just make sure you align your code correctly otherwise you will have leading white space in front each line.

很高兴知道：只要确保正确对齐代码，否则每行前面都会有前导空格。

---

---

By the way:you shouldn't call your variable strbecause that's the name of the datatype itself.

顺便说一句：您不应该调用您的变量，str因为那是数据类型本身的名称。

Sources for formatted strings:

格式化字符串的来源：

• What's new in Python 3.6
• PEP498

• Python 3.6 中的新功能
• PEP498