如何删除Matplotlib图中的线

Question

我该如何删除matplotlib轴的一条线（或多条线），使其实际上收集到垃圾并释放回内存？以下代码似乎删除了该行，但是从不释放内存（即使显式调用gc.collect()）

from matplotlib import pyplot
import numpy
a = numpy.arange(int(1e7))
# large so you can easily see the memory footprint on the system monitor.
fig = pyplot.Figure()
ax  = pyplot.add_subplot(1, 1, 1)
lines = ax.plot(a) # this uses up an additional 230 Mb of memory.
# can I get the memory back?
l = lines[0]
l.remove()
del l
del lines
# not releasing memory
ax.cla() # this does release the memory, but also wipes out all other lines.

Answer 1

我正在展示lines.pop(0) l.remove()和结合del l使用的技巧。

from matplotlib import pyplot
import numpy, weakref
a = numpy.arange(int(1e3))
fig = pyplot.Figure()
ax  = fig.add_subplot(1, 1, 1)
lines = ax.plot(a)

l = lines.pop(0)
wl = weakref.ref(l)  # create a weak reference to see if references still exist
#                      to this object
print wl  # not dead
l.remove()
print wl  # not dead
del l
print wl  # dead  (remove either of the steps above and this is still live)

我检查了您的大型数据集，并在系统监视器上也确认了内存的释放。

当然，更简单的方法（当不进行故障排除时）是从列表中弹出它并remove在不创建硬引用的情况下调用该行对象：

lines.pop(0).remove()