53 lines
1.5 KiB
Markdown
53 lines
1.5 KiB
Markdown
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---
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title: Python f-strings
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localeTitle: Python f字符串
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---
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# Python中的f字符串
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在Python 3.6版中，实现了一种格式化字符串的新方法。新方法称为文字字符串插值（通常称为f字符串）。
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f-string的使用允许程序员以干净简洁的方式动态地将变量插入到字符串中。除了将变量插入字符串之外，此功能还为程序员提供了计算表达式，连接集合内容，甚至调用f字符串中的函数的能力。
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要在f字符串中执行这些动态行为，我们将它们包装在字符串中的大括号内，并将小写字母f前置到字符串的开头（在开头引号之前）。
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### 例子
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1. 在运行时动态地将变量插入到字符串中：
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```python
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name = 'Jon Snow'
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greeting = f'Hello! {name}'
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print(greeting)
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```
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2. 评估字符串中的表达式： `python val1 = 2 val2 = 3 expr = f'The sum of {val1} + {val2} is {val1 + val2}' print(expr)`
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3. 调用函数并在字符串中插入输出：
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```python
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def sum(*args):
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result = 0
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for arg in args:
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result += arg
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return result
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func = f'The sum of 3 + 5 is {sum(3, 5)}'
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print(func)
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```
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4. 在字符串中连接集合的内容：
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```python
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fruits = ['Apple', 'Banana', 'Pear']
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list_str = f'List of fruits: {", ".join(fruits)}'
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print(list_str)
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```
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### 来源
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https://www.python.org/dev/peps/pep-0498/
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