这将在GUI中显示图形:
import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [1, 4, 9])
plt.show()
但我如何将图形保存到文件(例如foo.png)中?
这将在GUI中显示图形:
import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [1, 4, 9])
plt.show()
但我如何将图形保存到文件(例如foo.png)中?
当前回答
除上述内容外,我还为名称添加了__file__,以便图片和Python文件获得相同的名称。我还添加了一些参数以使它看起来更好:
# Saves a PNG file of the current graph to the folder and updates it every time
# (nameOfimage, dpi=(sizeOfimage),Keeps_Labels_From_Disappearing)
plt.savefig(__file__+".png",dpi=(250), bbox_inches='tight')
# Hard coded name: './test.png'
其他回答
根据问题Matplotlib(pyplot)savefig输出空白图像。
有一点需要注意:如果您使用plt.show,并且它应该在plt.savefig之后,否则您将给出一个空白图像。
详细示例:
import numpy as np
import matplotlib.pyplot as plt
def draw_result(lst_iter, lst_loss, lst_acc, title):
plt.plot(lst_iter, lst_loss, '-b', label='loss')
plt.plot(lst_iter, lst_acc, '-r', label='accuracy')
plt.xlabel("n iteration")
plt.legend(loc='upper left')
plt.title(title)
plt.savefig(title+".png") # should before plt.show method
plt.show()
def test_draw():
lst_iter = range(100)
lst_loss = [0.01 * i + 0.01 * i ** 2 for i in xrange(100)]
# lst_loss = np.random.randn(1, 100).reshape((100, ))
lst_acc = [0.01 * i - 0.01 * i ** 2 for i in xrange(100)]
# lst_acc = np.random.randn(1, 100).reshape((100, ))
draw_result(lst_iter, lst_loss, lst_acc, "sgd_method")
if __name__ == '__main__':
test_draw()
您可以使用任何扩展名(png、jpg等)和所需的分辨率保存图像。这里有一个功能来保存您的身材。
import os
def save_fig(fig_id, tight_layout=True, fig_extension="png", resolution=300):
path = os.path.join(IMAGES_PATH, fig_id + "." + fig_extension)
print("Saving figure", fig_id)
if tight_layout:
plt.tight_layout()
plt.savefig(path, format=fig_extension, dpi=resolution)
“fig_id”是您希望保存数字的名称。希望它有帮助:)
如果像我一样使用Spyder IDE,则必须禁用交互模式:
plt.ioff()
(此命令在科学启动时自动启动)
如果要再次启用,请使用:
plt.ion()
import datetime
import numpy as np
from matplotlib.backends.backend_pdf import PdfPages
import matplotlib.pyplot as plt
# Create the PdfPages object to which we will save the pages:
# The with statement makes sure that the PdfPages object is closed properly at
# the end of the block, even if an Exception occurs.
with PdfPages('multipage_pdf.pdf') as pdf:
plt.figure(figsize=(3, 3))
plt.plot(range(7), [3, 1, 4, 1, 5, 9, 2], 'r-o')
plt.title('Page One')
pdf.savefig() # saves the current figure into a pdf page
plt.close()
plt.rc('text', usetex=True)
plt.figure(figsize=(8, 6))
x = np.arange(0, 5, 0.1)
plt.plot(x, np.sin(x), 'b-')
plt.title('Page Two')
pdf.savefig()
plt.close()
plt.rc('text', usetex=False)
fig = plt.figure(figsize=(4, 5))
plt.plot(x, x*x, 'ko')
plt.title('Page Three')
pdf.savefig(fig) # or you can pass a Figure object to pdf.savefig
plt.close()
# We can also set the file's metadata via the PdfPages object:
d = pdf.infodict()
d['Title'] = 'Multipage PDF Example'
d['Author'] = u'Jouni K. Sepp\xe4nen'
d['Subject'] = 'How to create a multipage pdf file and set its metadata'
d['Keywords'] = 'PdfPages multipage keywords author title subject'
d['CreationDate'] = datetime.datetime(2009, 11, 13)
d['ModDate'] = datetime.datetime.today()
考虑到今天(提出这个问题时还不可用)许多人使用Jupyter Notebook作为python控制台,有一种极其简单的方法可以将绘图保存为.png,只需从Jupyter记事本调用matplotlib的pylab类,绘制图形“内联”Jupyter单元格,然后将该图形/图像拖到本地目录。别忘了%matplotlib在第一行中内联!