mirror of
https://github.com/erg-lang/erg.git
synced 2025-10-02 05:31:11 +00:00
45 lines
No EOL
1.4 KiB
Markdown
45 lines
No EOL
1.4 KiB
Markdown
# 擴展語法
|
||
|
||
[](https://gezf7g7pd5.execute-api.ap-northeast-1.amazonaws.com/default/source_up_to_date?owner=erg-lang&repos=erg&ref=main&path=doc/EN/syntax/28_spread_syntax.md&commit_hash=06f8edc9e2c0cee34f6396fd7c64ec834ffb5352)
|
||
|
||
在分解賦值中，將 `...` 放在變量前面會將所有剩余元素展開到該變量中。這稱為展開賦值
|
||
|
||
```python
|
||
[x,...y] = [1, 2, 3]
|
||
assert x == 1
|
||
assert y == [2, 3]
|
||
x, ...y = (1, 2, 3)
|
||
assert x == 1
|
||
assert y == (2, 3)
|
||
```
|
||
|
||
## 提取賦值
|
||
|
||
如果在 `...` 之后沒有寫入任何內容，則忽略并分配剩余的元素。這種類型的賦值具體稱為提取賦值
|
||
提取分配是一種方便的語法，用于本地化模塊或記錄中的特定屬性
|
||
|
||
```python
|
||
{sin; cos; tan; ..} = import "math"
|
||
```
|
||
|
||
|
||
之后，您可以在本地使用`sin，cos，tan`
|
||
|
||
您可以對記錄執行相同的操作。
|
||
|
||
```python
|
||
record = {x = 1; y = 2}
|
||
{x; y; ...} = record
|
||
```
|
||
|
||
如果要全部展開，請使用`{*}=record`。它在OCaml中是`open`。
|
||
|
||
```python
|
||
record = {x = 1; y = 2}
|
||
{*} = records
|
||
assert x == 1 and y == 2
|
||
```
|
||
|
||
<p align='center'>
|
||
<a href='./27_comprehension.md'>上一頁</a> | <a href='./29_decorator.md'>下一頁</a>
|
||
</p> |