# 语法综述

xlwings的对象模型和VBA的非常相似。

后面所有的示例代码都依赖下面的模块导入语句：

```pycon
>>> import xlwings as xw
```

## 活动对象

```python
# Active app (i.e. Excel instance)
>>> app = xw.apps.active

# Active book
>>> wb = xw.books.active  # in active app
>>> wb = app.books.active  # in specific app

# Active sheet
>>> sheet = xw.sheets.active  # in active book
>>> sheet = wb.sheets.active  # in specific book
```

A Range can be instantiated with A1 notation, a tuple of Excel's 1-based indices, or a named range:

```python
import xlwings as xw
sheet1 = xw.Book("MyBook.xlsx").sheets[0]

sheet1.range("A1")
sheet1.range("A1:C3")
sheet1.range((1,1))
sheet1.range((1,1), (3,3))
sheet1.range("NamedRange")

# Or using index/slice notation
sheet1["A1"]
sheet1["A1:C3"]
sheet1[0, 0]
sheet1[0:4, 0:4]
sheet1["NamedRange"]
```

## 对象的完全限定

Round brackets follow Excel's behavior (i.e. 1-based indexing), while square brackets use Python's 0-based indexing/slicing.
As an example, the following expressions all reference the same range:

```python
xw.apps[763].books[0].sheets[0].range('A1')
xw.apps(10559).books(1).sheets(1).range('A1')
xw.apps[763].books['Book1'].sheets['Sheet1'].range('A1')
xw.apps(10559).books('Book1').sheets('Sheet1').range('A1')
```

Note that the apps keys are different for you as they are the process IDs (PID). You can get the list of your PIDs via
`xw.apps.keys()`.

## App context manager

If you want to open a new Excel instance via `App()`, you usually should use `App` as a context manager as this will make sure that the Excel instance is closed and cleaned up again properly:

```python
with xw.App() as app:
    book = app.books['Book1']
```

## 区域索引/切片

区域对象支持索引和切片，下面是一些例子：

```pycon
>>> myrange = xw.Book().sheets[0].range('A1:D5')
>>> myrange[0, 0]
 <Range [Workbook1]Sheet1!$A$1>
>>> myrange[1]
 <Range [Workbook1]Sheet1!$B$1>
>>> myrange[:, 3:]
<Range [Workbook1]Sheet1!$D$1:$D$5>
>>> myrange[1:3, 1:3]
<Range [Workbook1]Sheet1!$B$2:$C$3>
```

## 区域快捷方式

Sheet objects offer a shortcut for range objects by using index/slice notation on the sheet object. This evaluates to either
`sheet.range` or `sheet.cells` depending on whether you pass a string or indices/slices:

```pycon
>>> sheet = xw.Book().sheets['Sheet1']
>>> sheet['A1']
<Range [Book1]Sheet1!$A$1>
>>> sheet['A1:B5']
<Range [Book1]Sheet1!$A$1:$B$5>
>>> sheet[0, 1]
<Range [Book1]Sheet1!$B$1>
>>> sheet[:10, :10]
<Range [Book1]Sheet1!$A$1:$J$10>
```

## 对象层次结构

下面用一个例子来说明xlwings中从app到range的层次顺序和反过来从range到app的层次顺序：

```pycon
>>> myrange = xw.apps[10559].books[0].sheets[0].range('A1')
>>> myrange.sheet.book.app
<Excel App 10559>
```