CODEWITHSUNDEEP
pythonmatplotlib
Sam Weisenthal
Sam Weisenthal

Reputation: 2951

Use Line2D to plot line in matplotlib

I have the data:

x = [10,24,23,23,3]
y = [12,2,3,4,2]

I want to plot it using matplotlib.lines.Line2D(xdata, ydata). I tried:

import matplotlib.lines
matplotlib.lines.Line2D(x, y)

But how do I show the line?

Upvotes: 21

Views: 76678

Answers (5)

mins
mins

Reputation: 7504

If you want to add a Line2D instance to an existing Axes instance ax:

ax.add_line(line)

See matplotlib.axes.Axes.add_line. This will use all attributes of the line, like width and color.

If you don't have an Axes instance, you can create one on an existing Figure instance fig using:

ax = fig.add_axes((x, y, w, h))

See matplotlib.figure.Figure.add_axes. The tuple is the position in figure coordinates: x and y between 0 and 1, w and h whatever size, also in figure coordinate system.

If you don't have a figure, you can create one, or just use the static dedicated method:

new_line = plt.plot(*line.get_data())

See matplotlib.pyplot.plot. This gets the tuple (xs, ys) describing the points of the Line2D and use it to create a new Line2D inserted into a new Axes of a new Figure.

Upvotes: 0

Atchariya My
Atchariya My

Reputation: 1

In [13]: import matplotlib.pyplot as plt

In [15]: from matplotlib.lines import Line2D

In [16]: fig = plt.figure()

In [17]: ax = fig.add_subplot(111)

In [18]: x = [10,24,23,23,3]

In [19]: y = [12,2,3,4,2]

In [20]: line = Line2D(x, y)

In [21]: ax.add_line(line) Out[21]: <matplotlib.lines.Line2D at 0x7f4c10732f60>

In [22]: ax.set_xlim(min(x), max(x)) Out[22]: (3, 24)

In [23]: ax.set_ylim(min(y), max(y)) Out[23]: (2, 12)

In [24]: plt.show()

Upvotes: 0

Andrew Pye
Andrew Pye

Reputation: 622

I have run into this problem when trying to replicate a line on two different plots. (mentioned in a comment "cannot put single artist in more than one figure) So assuming you already have a Line2D object from some other source and need it on new plot, the best way to add it to your plot is with:

line = Line2D(x, y)
plt.plot(*line.get_data(), ...)

You can also get a lot of the line's properties from its other "get" methods, found here.

Upvotes: 1

benjimin
benjimin

Reputation: 4890

The more common approach (not exactly what the questioner asked) is to use the plot interface. This involves Line2D behind the scenes. 

>>> x = [10,24,23,23,3]
>>> y = [12,2,3,4,2]
>>> import matplotlib.pyplot as plt
>>> plt.plot(x,y)
[<matplotlib.lines.Line2D object at 0x7f407c1a8ef0>]
>>> plt.show()

Upvotes: 11

awesoon
awesoon

Reputation: 33671

You should add the line to a plot and then show it:

In [13]: import matplotlib.pyplot as plt

In [15]: from matplotlib.lines import Line2D      

In [16]: fig = plt.figure()

In [17]: ax = fig.add_subplot(111)

In [18]: x = [10,24,23,23,3]

In [19]: y = [12,2,3,4,2]

In [20]: line = Line2D(x, y)

In [21]: ax.add_line(line)
Out[21]: <matplotlib.lines.Line2D at 0x7f4c10732f60>

In [22]: ax.set_xlim(min(x), max(x))
Out[22]: (3, 24)

In [23]: ax.set_ylim(min(y), max(y))
Out[23]: (2, 12)

In [24]: plt.show()

The result:

enter image description here

Upvotes: 30

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