问题描述
我找到了一些代码来生成一组小倍数,并且运行良好.
fig,axes = plt.subplots(6,3,figsize =(21,21))fig.subplots_adjust(hspace=.3, wspace=.175)对于 ax,zip 中的数据(axes.ravel(), clean_sets):ax.plot(data.ETo,o")
行 for ax, data in zip(axes.ravel(), clean_sets):
contians .ravel()
但我不明白这实际上在做什么或为什么有必要.
如果我看看文档我发现了以下内容:
返回连续的扁平化数组.
返回包含输入元素的一维数组.仅在需要时进行复制.
我猜对应于来自 plt.subplot()
的轴的返回是一个无法迭代的多维数组,但我真的不确定.一个简单的解释将不胜感激.
在这种情况下使用 .ravel()
的目的是什么?
您的猜测是正确的. plt.subplots()
返回一个由多个轴组成的 Axes
或 numpy
数组,具体取决于输入.如果用参数 nrows
和 ncols
定义2D网格,则返回的 numpy
数组也将是2D数组.
此行为在 pyplot.subplots
squeeze
参数中的文档,
squeeze
:布尔,可选,默认值:True
如果为True,则从返回的Axes对象中挤出额外的尺寸:
- 如果仅构造了一个子图(nrows = ncols = 1),则返回的单个Axes对象将作为标量返回.
- 对于 Nx1 或 1xN 子图,返回的对象是一个 1D numpy 对象数组,Axes 对象作为 numpy 1D 数组返回.
- 对于 NxM,N>1 和 M>1 的子图作为二维数组返回.
如果为 False,则根本不进行压缩:返回的 Axes 对象始终是包含 Axes 实例的二维数组,即使它最终是 1x1.
因为这里有 plt.subplots(6,3)
,因此 N>1, M>1
,结果对象必然是一个 2D 数组,独立于 squeeze
设置为什么.
这使得有必要展平此数组,以便能够对其进行 zip
压缩.选项是
zip(axes.ravel())
zip(axes.flatten())
-
zip(axes.flat)
I found some code to generate a set of small multiples and it is working perfectly.
fig, axes = plt.subplots(6,3, figsize=(21,21))
fig.subplots_adjust(hspace=.3, wspace=.175)
for ax, data in zip(axes.ravel(), clean_sets):
ax.plot(data.ETo, "o")
The line for ax, data in zip(axes.ravel(), clean_sets):
contians .ravel()
but I do not understand what this is actually doing or why it is necessary.
If I take a look at the docs I find the following:
I guess the return that corresponds to axes from plt.subplot()
is a multidimensional array that can't be iterated over, but really I'm not sure. A simple explanation would be greatly appreciated.
What is the purpose of using .ravel()
in this case?
Your guess is correct. plt.subplots()
returns either an Axes
or a numpy
array of several axes, depending on the input. In case a 2D grid is defined by the arguments nrows
and ncols
, the returned numpy
array will be a 2D array as well.
This behaviour is explained in the pyplot.subplots
documentation inside the squeeze
argument,
- for Nx1 or 1xN subplots, the returned object is a 1D numpy object array of Axes objects are returned as numpy 1D arrays.
- for NxM, subplots with N>1 and M>1 are returned as a 2D arrays.
Since here you have plt.subplots(6,3)
and hence N>1, M>1
, the resulting object is necessarily a 2D array, independent of what squeeze
is set to.
This makes it necessary to flatten this array in order to be able to zip
it. Options are
zip(axes.ravel())
zip(axes.flatten())
zip(axes.flat)
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