Matplotlib Xticks Values in Bar Chart

Question

I have this code and im trying to make a graph. All values are in the lists are correct. However, i have problem in x axis. First, there is a gap between first two ticks. I read all matplotlib in their site but couldn find anyting useful for this problem. I'm all confused about xticks function. This is my graph

plt.bar(Valloc1,[diabete[w] for w in sorted(diabete.keys())], width=0.2,)

plt.bar(Valloc2,[not_diabete[w] for w in sorted(not_diabete.keys())], width=0.1, )

plt.xticks(all_years, rotation = '65')
plt.legend(['Diabete','Not-Diabete'])
plt.xlabel('Years')
plt.ylabel('# of patients')
plt.legend()
plt.show()

I have tried this line but everything went worse.

plt.xticks(range(all_years),all_years, rotation = '65')

I also want that two bars to be beside not overlap. Just like this : Bars side-by-side

My variables are:

Valloc1 = [i for i in range(52)]
diabete = {{1967: 5, 1986: 13, 1985: 9, 1996: 5, 1984: 10, 1987: 6, 1991: 8...}

Set the `xticks` as consecutive numerical values and the actual years only as labels: `plt.xticks([i for i in range(len(all_years))], all_years, rotation = '65')`. — Thomas Kühn, Dec 15 '17 at 20:20
If you want your bars side by side, you also have to specify `x` values in the `bar` plot and shift all `x` values by a constant in the second `bar` command. That means, define your `xtick` positions beforehand (best to use numpy), make the two plots and then adjust the labels. — Thomas Kühn, Dec 15 '17 at 20:22
Possible duplicate of [Change matplotlib.bar Order in python 2.7](https://stackoverflow.com/questions/47731289/change-matplotlib-bar-order-in-python-2-7) — Thomas Kühn, Dec 15 '17 at 20:26

score 18 · Accepted Answer · answered Dec 19 '17 at 19:01

Here is an example how to solve your problem. As you don't provide the data, I first generate some random data in the example below and then visualise it as a bar plot like you requested:

from matplotlib import pyplot as plt
import numpy as np

##generating some data
years = [1936, 1945]+[i for i in range(1947,1997)]
data1 = np.random.rand(len(years))
data2 = np.random.rand(len(years))

diabete = {key: val for key,val in zip(years, data1)}
not_diabete = {key: val for key,val in zip(years, data2)}



##the actual graph:
fig, ax = plt.subplots(figsize = (10,4))

idx = np.asarray([i for i in range(len(years))])

width = 0.2

ax.bar(idx, [val for key,val in sorted(diabete.items())], width=width)
ax.bar(idx+width, [val for key,val in sorted(not_diabete.items())], width=width)

ax.set_xticks(idx)
ax.set_xticklabels(years, rotation=65)
ax.legend(['Diabete', 'Non-Diabete'])
ax.set_xlabel('years')
ax.set_ylabel('# of patients')

fig.tight_layout()

plt.show()

The result looks like this:

Matplotlib Xticks Values in Bar Chart

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