[英]Can't “import matplotlib.pyplot as plt”
Can't get matplotlib.pyplot to import. 无法获取要导入的matplotlib.pyplot。 Have upgraded my pi to Jessie, Python3.4, installed matplotlib from source.
已将我的pi升级到Jessie,Python3.4,从源代码安装了matplotlib。 Here's some code I got from this site and modified to try and debug:
这是我从这个站点获得的一些代码,并经过修改以尝试和调试:
#!/usr/bin/python3.4
#find_backends.py
#from pylab import *
import time
import matplotlib as mpl
import matplotlib.backends
#import matplotlib.pyplot as p
import os.path
def is_backend_module(fname):
"""Identifies if a filename is a matplotlib backend module"""
return fname.startswith('backend_') and fname.endswith('.py')
def backend_fname_formatter(fname):
"""Removes the extension of the given filename, then takes away the leading 'backend_'."""
return os.path.splitext(fname)[0][8:]
print("thebackend= " + mpl.get_backend())
# get the directory where the backends live
backends_dir = os.path.dirname(matplotlib.backends.__file__)
print("backends_dir: \t" + str(backends_dir))
# filter all files in that directory to identify all files which provide a backend
backend_fnames = filter(is_backend_module, os.listdir(backends_dir))
backends = [backend_fname_formatter(fname) for fname in backend_fnames]
print("supported backends: \t" + str(backends))
# validate backends
backends_valid = []
for b in backends:
try:
p.switch_backend(b)
backends_valid += [b]
except:
continue
print("valid backends: \t" + str(backends_valid))
# try backends performance
for b in backends_valid:
ion()
try:
p.switch_backend(b)
clf()
tstart = time.time() # for profiling
x = arange(0,2*pi,0.01) # x-array
line, = plot(x,sin(x))
for i in arange(1,200):
line.set_ydata(sin(x+i/10.0)) # update the data
draw() # redraw the canvas
print(b + ' FPS: \t' , 200/(time.time()-tstart))
ioff()
except:
print(b + " error :(")
results in: 结果是:
thebackend= GTK3Agg
backends_dir: /usr/local/lib/python3.4/dist-packages/matplotlib/backends
supported backends: ['agg', 'qt5', 'mixed', 'template', 'cairo', 'gtkcairo', 'gtk3', 'webagg_core', 'gtk3cairo', 'pdf', 'gdk', 'ps', 'wx', 'wxagg', 'qt5agg', 'macosx', 'qt4agg', 'qt4', 'nbagg', 'gtkagg', 'tkagg', 'pgf', 'webagg', 'svg', 'gtk3agg', 'gtk']
valid backends: []
------------------
(program exited with code: 0)
Press return to continue
So the backend is GTK3AGG? 那么后端是GTK3AGG? Why doesn't the capitalization match the supported backends list?
为什么大小写不匹配支持的后端列表? If I remove # from #import matplotlib.pyplot as p the import will fail and I get:
如果我从#import matplotlib.pyplot删除#作为p导入将失败,我得到:
** (find_backends.py:1057): WARNING **: Error retrieving accessibility bus address: org.freedesktop.DBus.Error.ServiceUnknown: The name org.a11y.Bus was not provided by any .service files
Traceback (most recent call last):
File "/usr/local/lib/python3.4/dist-packages/matplotlib/backends/backend_cairo.py", line 33, in <module>
import cairocffi as cairo
ImportError: No module named 'cairocffi'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/local/lib/python3.4/dist-packages/matplotlib/backends/backend_cairo.py", line 36, in <module>
import cairo
ImportError: No module named 'cairo'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "find_backends.py", line 8, in <module>
import matplotlib.pyplot as p
File "/usr/local/lib/python3.4/dist-packages/matplotlib/pyplot.py", line 115, in <module>
_backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
File "/usr/local/lib/python3.4/dist-packages/matplotlib/backends/__init__.py", line 32, in pylab_setup
globals(),locals(),[backend_name],0)
File "/usr/local/lib/python3.4/dist-packages/matplotlib/backends/backend_gtk3agg.py", line 12, in <module>
from .backend_cairo import cairo, HAS_CAIRO_CFFI
File "/usr/local/lib/python3.4/dist-packages/matplotlib/backends/backend_cairo.py", line 38, in <module>
raise ImportError("Cairo backend requires that cairocffi or pycairo is installed.")
ImportError: Cairo backend requires that cairocffi or pycairo is installed.
------------------
(program exited with code: 1)
Press return to continue
cairo is listed as a supported backend but fails here. cairo被列为受支持的后端,但在此处失败。 I'm not sure what to try next.
我不确定下一步该尝试什么。 I have been trying to get a matplotlib example to work off and on for about 2 years from the book 'Raspberry Pi Cookbook for Python Programmers'.
我一直试图从“Raspberry Pi Cookbook for Python Programmers”一书中获得一个matplotlib示例,以便继续工作大约2年。 I'm almost ready to give up again.
我几乎准备好再次放弃。
The answer was in macplotlib.use() . 答案是在macplotlib.use()中 。 As it notes, you must use use() before the matplotlib.pyplot import.
如上所述,您必须在matplotlib.pyplot导入之前使用use()。 I had to try several of the backbends found above to find one that works.
我不得不尝试上面找到的几个后弯来找到一个有效的。
import numpy as np
import matplotlib as mpl
mpl.use('tkagg') #YAAA!! this finally makes the Damn thing work
import matplotlib.pyplot as plt
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