I am trying to save a pyplot generated histogram . But when i try to save this it gives me an error savefig() takes 2 positional arguments but 3 were given. How to overcome this error?
Here is my code:
dir1=r"C:\Users\USER\Handcrafted dataset\histogram"
for i,img in enumerate(images1):
plt.figure(figsize=(5,5))
plt.hist(img.ravel(),256,[0,256])
plt.savefig(dir1+"\\"+str(i)+".jpg",img)
plt.show()
Just remove img and try using and also comment out plt.show(). Since you are creating a new figure every time, I do not see why you need img
plt.savefig(dir1+"\\"+str(i)+".jpg")
# plt.show()
Related
let's say we have a df like below
I have plotted using seaborn. After that, I have extracted the xticks data. whenever I am running in the next cell, it is showing the correct result but in the same cell, its showing diff .highlighted both . what is the reason behind this and how to resolve.
PFB code:
DF part--->
df={'A':48,'B':12,'C':86}
df=pd.DataFrame(list(df.items()),columns=("name","score"))
df['score']=df['score']/100
df
plotting part --->
fig, ax=matplotlib.pyplot.subplots(figsize=(10,2))
g=sns.barplot(y='name',x='score',data=df,ax=ax)
ax.set_xticks([0,0.25,0.5,0.75,1.0])
ax.set_xticklabels(['0.00', 'bad','ok','good','v. good'])
ax.get_xticklabels()[1]
getting the xticks again in diff cell ---->
ax.get_xticklabels()[1]
Somehow you need to use plt.show() before calling ax.get_xticklabels(). I supose this variable is not computed until the graph is generated. So if you run the following in a single cell:
fig, ax=matplotlib.pyplot.subplots(figsize=(10,2))
g=sns.barplot(y='name',x='score',data=df,ax=ax)
ax.set_xticks([0,0.25,0.5,0.75,1.0])
ax.set_xticklabels(['0.00', 'bad','ok','good','v. good'])
for elem in ax.get_xticklabels():
print(elem)
plt.show()
for elem in ax.get_xticklabels():
print(elem)
You obtain the following:
I wasn't able to replicate your issue with the code you provided. Can you retry and include the cell execution indicators on the left edge?
I have plotted a histogram and would like to modify it, then re-plot it. It won't plot again without redefining the Figure and Axes object definitions. I'm using Jupyter Notebook, and I'm new to matplotlib, so I don't know if this is something that I'm not understanding about matplotlib, if it's an issue with the Jupyter Notebook or something else.
Here's my 1st block of code:
"""Here's some data."""
some_data = np.random.randn(150)
"""Here I define my `Figure` and `Axes` objects."""
fig, ax = plt.subplots()
"""Then I make a histogram from them, and it shows up just fine."""
ax.hist(some_data, range=(0, 5))
plt.show()
Here's the output from my 1st block of code:
Here's my 2nd block of code:
"""Here I modify the parameter `bins`."""
ax.hist(some_data, bins=20, range=(0, 5))
"""When I try to make a new histogram, it doesn't work."""
plt.show()
My 2nd block of code generates no visible output, which is the problem.
Here's my 3rd and final block of code:
"""But it does work if I define new `Figure` and `Axes` objects.
Why is this?
How can I display new, modified plots without defining new `Figure` and/or `Axes` objects? """
new_fig, new_ax = plt.subplots()
new_ax.hist(some_data, bins=20, range=(0, 5))
plt.show()
Here's the output from my 3rd and final block of code:
Thanks in advance.
When you generate a figure or an axis, it remains accessible for rendering or display until it's used for rendering or display. Once you execute plt.show() in your first block, the ax becomes unavailable. Your 3rd block of code is showing a plot because you're regenerating the figure and axes.
I'm trying to conciliate dots annotation in a Matplotlib scatter plot with a manual limit setting, but I either got an error message or I get a design problem.
Here is my code :
fig, ax = plt.subplots(figsize = (20,10)) #manual limit setting
plt.axis([-2,3,-2.5,5])
plt.scatter(x, y)
for i, txt in enumerate(n): #dot annotation
ax.annotate(txt, (x[i], y[i]))
Here is a screen cap of the output (I got the final scatter plot as a small rectangle located in the left corner of a big white rectangle :
I tried this also :
fig, ax = plt.subplots(figsize = (20,10))
ax = plt.axis([-2,3,-2.5,5])
plt.scatter(x, y)
for i, txt in enumerate(n):
ax.annotate(txt, (x[i], y[i]))
But of course I got the following error message (even though the chart correctly displays, but without the labels next to each corresponding dot).
AttributeError: 'list' object has no attribute 'annotate'
The error arises because my loop tries to iterate through ax = plt.axis([-2,3,-2.5,5]), which doesn't make sense indeed.
Any solution to overcome this issue ?
Thank you
The problem occurs because of the special casing of texts when it comes to clipping. Usually you might want text outside the axes to be shown. Therefore annotations and text have a annotation_clip argument. However, this interferes with the bbox_inches="tight" option when saving annotations, because the annotations is then still considered part of the layout and hence the figure takes annotations outside the axes still into account.
Two solutions:
Set annotation_clip and clip_on. I.e. You may explicitely tell the annotation to clip at the axes:
ax.annotate(txt, (x[i], y[i]), annotation_clip=True, clip_on=True)
Set bbox_inches to None. When using the IPython inline backend you can tell it not to expand the figure via
%config InlineBackend.print_figure_kwargs = {'bbox_inches':None}
in a cell before starting to create your content. (This is seen in this answer)
I can't replicate the first issue (tried in versions 2.2.3, 3.1.1, 3.1.2) - I get this (using random data). Try upgrading your version of matplotlib or using
plt.savefig('/path/to/output/image.png')
To save the figure to the disk instead of showing it directly and see if the problem persists.
I can however explain the error
AttributeError: 'list' object has no attribute 'annotate'
This occurs because plt.axis() returns [xmin, xmax, ymin, ymax], not an axes instance (fig, ax = plt.subplots(figsize=(20,10) returns an axes instance to ax).
I am creating a scatter plot with color map based on some values and I am trying to make part of the x_axis label italic (inspired mostly by this post -> https://stackoverflow.com/a/8384685/1093485) but I am getting a LaTeX error that I can not explain myself, I would appreciate if anyone is able to explain what is going wrong with this chunk?
Minimum code required to reproduce problem here:
#! /usr/bin/env python
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import rc
X = [1257.422648,1298.449197,1339.475746,1419.475471,1455.52309,1460.50202,1485.533655]
Y = [21.84637515,18.19617016,22.29456694,5.228978612,3.888695726,12.36598466,4.201838517]
Z = [44.02797944,9.758071204,21.58997772,64.53887544,53.09630431,8.461254471,291.4311435]
# Enable LaTeX style
rc('text',usetex=True)
# Plot the data
fig=plt.figure()
fig.patch.set_facecolor('white')
ax=fig.add_subplot(111)
s = ax.scatter(X,Y,c=np.log(Z))
ax.set_xlabel(r'Analyte \textit{m/z}')
ax.xaxis.labelpad = 7.5
cb = plt.colorbar(mappable=s,ax=ax)
plt.show()
Commenting the rc('text',usetex=True) causes the plot to show but obviously without italics. The whole traceback is rather large but seems to revolve around this part (if I read it correctly):
RuntimeError: LaTeX was not able to process the following string:
'$1450$'
Anyone have a suggestion on what to do to isolate the problem?
I'm trying to do a basic line graph here, but I can't seem to figure out how to adjust my x axis.
And here is the error I get when I try adjusting my range.
from pylab import *
plot ( range(0,11),[9,4,5,2,3,5,7,12,2,3],'.-',label='sample1' )
plot ( range(0,11),[12,5,33,2,4,5,3,3,22,10],'o-',label='sample2' )
xlabel('x axis')
ylabel('y axis')
title('my sample graphs')
legend(('sample1','sample2'))
savefig("sampleg.png",dpi=(640/8))
show()
File "C:\Python26\lib\site-packages\matplotlib\axes.py", line 228, in _xy_from_xy
raise ValueError("x and y must have same first dimension")
ValueError: x and y must have same first dimension
I want my range to be a list of strings: ["12/1/2007","12/1/2008", "12/1/2009","12/1/2010"]
Any suggestions?
Honestly, I found the code online and was trying to rewrite it to properly understand it. I think I'm going to start from scratch so that I know what I'm doing but I need help on where to start.
I posted another question which explains what I want to do here:
Using PyLab to create a 2D graph from two separate lists
range(0,11) should be range(0,10).
In addition to Steve's observation: If your points are always some y-value at the same consecutive integer x's, matplotlib makes the range even implicit.
plot([9,4,5,2,3,5,7,12,2,3],'.-',label='sample1')