Plot a bar using matplotlib using a dictionary

Question

Is there any way to plot a bar plot using matplotlib using data directly from a dict?

My dict looks like this:

D = {u'Label1':26, u'Label2': 17, u'Label3':30}

I was expecting

fig = plt.figure(figsize=(5.5,3),dpi=300)
ax = fig.add_subplot(111)
bar = ax.bar(D,range(1,len(D)+1,1),0.5)

to work, but it does not.

Here is the error:

>>> ax.bar(D,range(1,len(D)+1,1),0.5)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/site-packages/matplotlib/axes.py", line 4904, in bar
    self.add_patch(r)
  File "/usr/local/lib/python2.7/site-packages/matplotlib/axes.py", line 1570, in add_patch
    self._update_patch_limits(p)
  File "/usr/local/lib/python2.7/site-packages/matplotlib/axes.py", line 1588, in _update_patch_limits
    xys = patch.get_patch_transform().transform(vertices)
  File "/usr/local/lib/python2.7/site-packages/matplotlib/patches.py", line 580, in get_patch_transform
    self._update_patch_transform()
  File "/usr/local/lib/python2.7/site-packages/matplotlib/patches.py", line 576, in _update_patch_transform
    bbox = transforms.Bbox.from_bounds(x, y, width, height)
  File "/usr/local/lib/python2.7/site-packages/matplotlib/transforms.py", line 786, in from_bounds
    return Bbox.from_extents(x0, y0, x0 + width, y0 + height)
TypeError: coercing to Unicode: need string or buffer, float found

Can you share specifically what does not work? Do you get an exception? What exception? Share as much information as possible. — Inbar Rose
– Inbar Rose, Commented Apr 15, 2013 at 8:38
@InbarRose sorry, I have updated the question with the error it shows... something concerning string or buffer... I don't understand this error message. — otmezger
– otmezger, Commented Apr 15, 2013 at 8:40
It's not clear what you want to achieve, but in ax.bar(D,range(1,len(D)+1,1),0.5) the first argument should be a list of numbers, in your case D.values(). — adrianp
– adrianp, Commented Apr 15, 2013 at 8:43
A one-liner is not possible for this, at least to my knowledge. — adrianp
– adrianp, Commented Apr 15, 2013 at 9:03
You might want to submit a feature request to the github site for this, because it does seem useful. — tacaswell
– tacaswell, Commented Apr 15, 2013 at 16:05

Engineero · Accepted Answer · 2019-04-29 20:10:54Z

208

You can do it in two lines by first plotting the bar chart and then setting the appropriate ticks:

import matplotlib.pyplot as plt

D = {u'Label1':26, u'Label2': 17, u'Label3':30}

plt.bar(range(len(D)), list(D.values()), align='center')
plt.xticks(range(len(D)), list(D.keys()))
# # for python 2.x:
# plt.bar(range(len(D)), D.values(), align='center')  # python 2.x
# plt.xticks(range(len(D)), D.keys())  # in python 2.x

plt.show()

Note that the penultimate line should read plt.xticks(range(len(D)), list(D.keys())) in python3, because D.keys() returns a generator, which matplotlib cannot use directly.

edited Apr 29, 2019 at 20:10

Engineero

13k5 gold badges56 silver badges79 bronze badges

answered Apr 15, 2013 at 12:13

David Zwicker

24.4k8 gold badges68 silver badges80 bronze badges

Sign up to request clarification or add additional context in comments.

12 Comments

tacaswell Over a year ago

you can of course wrap those two lines up in a function and then it becomes a one-liner ;)

Mark Over a year ago

If you use figure and axes objects, it's ax.set_xticklabels

moldovean Over a year ago

thanks! But I have some estetic issues with plt.xticks, could you please tell us how to move them vertically from horizontally.

ssm Over a year ago

are the key-value pairs aligned when the dict is not sorted?

David Zwicker Over a year ago

Python dicts cannot be sorted. Consequently, the order is always arbitrary. However, the keys and values are always aligned with the above code.

|

ImportanceOfBeingErnest · Accepted Answer · 2018-11-22 13:35:52Z

117

It's a little simpler than most answers here suggest:

import matplotlib.pyplot as plt

D = {u'Label1':26, u'Label2': 17, u'Label3':30}
plt.bar(*zip(*D.items()))
plt.show()

answered Nov 22, 2018 at 13:35

ImportanceOfBeingErnest

342k61 gold badges737 silver badges771 bronze badges

1 Comment

Sahar Millis Over a year ago

this should be the answer. tnx

Engineero · Accepted Answer · 2019-04-29 20:11:05Z

41

For future reference, the above code does not work with Python 3. For Python 3, the D.keys() needs to be converted to a list.

import matplotlib.pyplot as plt

D = {u'Label1':26, u'Label2': 17, u'Label3':30}

plt.bar(range(len(D)), D.values(), align='center')
plt.xticks(range(len(D)), list(D.keys()))

plt.show()

edited Apr 29, 2019 at 20:11

Engineero

13k5 gold badges56 silver badges79 bronze badges

answered Mar 18, 2015 at 5:25

Michael T

1,0439 silver badges13 bronze badges

Comments

Hong Zhao · Accepted Answer · 2021-01-16 23:00:51Z

17

Why not just:

names, counts = zip(*D.items())
plt.bar(names, counts)

answered Jan 16, 2021 at 23:00

Hong Zhao

3123 silver badges5 bronze badges

Comments

Stephen Rauch · Accepted Answer · 2018-01-26 04:25:02Z

The best way to implement it using matplotlib.pyplot.bar(range, height, tick_label) where the range provides scalar values for the positioning of the corresponding bar in the graph. tick_label does the same work as xticks(). One can replace it with an integer also and use multiple plt.bar(integer, height, tick_label). For detailed information please refer the documentation.

import matplotlib.pyplot as plt

data = {'apple': 67, 'mango': 60, 'lichi': 58}
names = list(data.keys())
values = list(data.values())

#tick_label does the some work as plt.xticks()
plt.bar(range(len(data)),values,tick_label=names)
plt.savefig('bar.png')
plt.show()

Additionally the same plot can be generated without using range(). But the problem encountered was that tick_label just worked for the last plt.bar() call. Hence xticks() was used for labelling:

data = {'apple': 67, 'mango': 60, 'lichi': 58}
names = list(data.keys())
values = list(data.values())
plt.bar(0,values[0],tick_label=names[0])
plt.bar(1,values[1],tick_label=names[1])
plt.bar(2,values[2],tick_label=names[2])
plt.xticks(range(0,3),names)
plt.savefig('fruit.png')
plt.show()

anilbey · Accepted Answer · 2018-03-01 17:07:10Z

8

I often load the dict into a pandas DataFrame then use the plot function of the DataFrame.
Here is the one-liner:

pandas.DataFrame(D, index=['quantity']).plot(kind='bar')

answered Mar 1, 2018 at 17:07

anilbey

2,0274 gold badges25 silver badges46 bronze badges

Comments

Andronicus · Accepted Answer · 2019-08-14 18:21:18Z

6

Why not just:

import seaborn as sns

sns.barplot(list(D.keys()), list(D.values()))

edited Aug 14, 2019 at 18:21

Andronicus

26.2k18 gold badges55 silver badges92 bronze badges

answered Aug 14, 2019 at 18:02

rwilsker

1171 silver badge4 bronze badges

Comments

reza imany · Accepted Answer · 2023-12-01 18:58:40Z

0

the easiest way for creating a bar graph from dictionary in python is using built-in function of python for dictionaries to retrive data, so if we had a dict like this:

values = {"foo":1,"bar":2,"hey":3}

we can create a bar plot like this:

fig,ax = plt.subplots()
ax.bar(values.keys(),values.values())

complete code and figure

edited Dec 1, 2023 at 18:58

answered Nov 30, 2023 at 11:24

reza imany

492 bronze badges

1 Comment

Jurakin Over a year ago

Please edit and change the variable name dict to something different (data, values, etc.). The code above works, but rewrites the built-in function.

Collectives™ on Stack Overflow

Plot a bar using matplotlib using a dictionary

8 Answers 8

12 Comments

1 Comment

Comments

Comments

Comments

Comments

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

8 Answers 8

12 Comments

1 Comment

Comments

Comments

Comments

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related