建立Matplotlib的LineCollection的细分列表 [英] Building a list of segments for a Matplotlib's LineCollection

问题描述

我想使用matplotlib.collections.LineCollection对象，从两个Numpy数组x和y

I want to use a matplotlib.collections.LineCollection object, starting from the two Numpy arrays x and y

>>> from matplotlib.collections import LineCollection
>>> from numpy import array, linspace

>>> x = linspace(0, 2, 5)
>>> y = 1-(1-x)**2

实例化LineCollection的唯一要求是由 segments 的列表组成的数据结构，每个 segment 都是 points的列表，每个 point 是一个元组.

The single thing that's strictly required to instantiate a LineCollection is a data structure composed of a list of segments, each segment being a list of points, each point being a tuple.

使用我的两个向量x和y我可以做到

Using my two vectors x and y I can do

>>> segments = np.array(list(zip( zip(x, x[1:]), zip(y, y[1:])))) .transpose((0,2,1))
>>> print(segments)
[[[0.   0.  ]
  [0.5  0.75]]

 [[0.5  0.75]
  [1.   1.  ]]

 [[1.   1.  ]
  [1.5  0.75]]

 [[1.5  0.75]
  [2.   0.  ]]]

我的问题.可以用一种不太隐秘的方式构造segments吗?

My question. Is it possible to construct segments in a less cryptic manner?

推荐答案

我总是喜欢将线段视为3D数组，第一个轴是线段，第二个是沿线段的坐标，第三个是线段分别是x和y坐标.

I always like to think of the segments as a 3D array, with the first axis being the linesegments, the second being the coordinates along the segments and the third being the x and y coordinates for each.

points = np.array([x, y]).T.reshape(-1,1,2)
segments = np.concatenate([points[:-1],points[1:]], axis=1)

或同样地

segments = np.stack((np.c_[x[:-1],x[1:]],np.c_[y[:-1],y[1:]]), axis=2)

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