如何在 Rmarkdown 文档中显示 Python 代码中的几何对象？

Posted 2023-02-14

【中文标题】如何在 Rmarkdown 文档中显示 Python 代码中的几何对象？

【英文标题】：How to display a geometric object from Python code in a Rmarkdown document?

【发布时间】：2022-01-18 17:25:44

【问题描述】：

我想在编织后在我的 rmarkdown 文档中显示一个点（如 in this tutorial）。

可重现的例子：

---
title: "Reprex"
output: html_document
---

```python
# Import necessary geometric objects from shapely module
from shapely.geometry import Point, LineString, Polygon

# Create Point geometric object(s) with coordinates
point1 = Point(2.2, 4.2)

point1
```

使用这段代码，我只得到以下输出：

## <shapely.geometry.point.Point object at 0x0000000026EEA0B8>

我怎样才能显示点的图像？

另外，我有兴趣在查看器/绘图窗格中显示它。

【参考方案1】：

首先，不确定这是否至关重要，但是，following the documentation，我们需要先添加这个块：

```r setup, include=FALSE
library(knitr)
library(reticulate)
knitr::knit_engines$set(python = reticulate::eng_python)
```

您想要获得的是特定于 Jupyter 的功能。我只能通过_repr_svg_() 函数将点转换为纯 SVG 来重现它：

```python
from shapely.geometry import Point, LineString, Polygon, MultiPoint

point1 = Point(2.2, 4.2)
point2 = Point(7.2, -25.1)
point3 = Point(9.26, -2.456)
point3D = Point(9.26, -2.456, 0.57)

multipoints = MultiPoint([point1, point2, point3, point3D])
svg = multipoints._repr_svg_()

# or, in your case

svg = point1._repr_svg_()
```

然后用 R 块显示它：

```r
htmltools::HTML(py$svg)
```

我尝试仅在 Python 端执行此操作（调用 r.HTML()），这只会导致文本输出。

请注意，这将导致以下警告：

sys:1: ShapelyDeprecationWarning: __len__ for multi-part geometries is deprecated and will be removed in Shapely 2.0. Check the length of the `geoms` property instead to get the  number of parts of a multi-part geometry.

但你可以忽略它，它仍然会画点：

完整代码：

---
title: "Reprex"
output: html_document
---

```r setup, include=FALSE
library(knitr)
library(reticulate)
knitr::knit_engines$set(python = reticulate::eng_python)
```

```python
from shapely.geometry import Point, LineString, Polygon, MultiPoint

point1 = Point(2.2, 4.2)
point2 = Point(7.2, -25.1)
point3 = Point(9.26, -2.456)
point3D = Point(9.26, -2.456, 0.57)

multipoints = MultiPoint([point1, point2, point3, point3D])
svg = multipoints._repr_svg_()

# or, in your case

svg = point1._repr_svg_()
```

```r
htmltools::HTML(py$svg)
```