freeCodeCamp/guide/chinese/python/learn-about-python-sets/index.md

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---
title: Learn About Python Sets
localeTitle: 了解Python集
---
Python中的`Set`是一种可变但无序的数据结构它只能包含_唯一的_元素。
**创建:**
`set`文字:
圆括号`{}` _不能_用于创建空集:
```python
>>> not_set = {} # set constructor must be used to make empty sets.
>>> type(not_set) # Empty curly brackets create empty dictionaries.
<class 'dict'>
```
您只能使用`set()`方法创建一个空集。
```python
>>> example_set = set()
>>> type(example_set)
<class 'set'>
```
但是,如果元素包含在大括号内,那么创建集合的语法是可以接受的。
```python
>>> example_set_2 = {1, 2, 3}
>>> type(example_set_2)
<class 'set'>
```
\`