displaying fixed width bars for all datasets in matplotlib

Question

I have the following datasets .I need to plot barchats for say 1,2 or all of them.When I plot the chart for a single data item (eg: xdata=[0] and ydata=[1000], xlabels=['first'] , the bar is sclaed to occupy the whole plot area.How do I restrict the barwidth to be say 0.45?

ydata=[1000,250,3000,500,3200,4000,2000]
xlabels=['first','sec','third','fourth','fifth','sixth','seventh']

barwidth = 0.45

import matplotlib.pyplot as plt

def create_bar_plot(entries):
    assert entries > 0    
    xdata = range(entries)
    xlabels=xlabels[:entries]
    xdata=xdata[:entries]
    ydata=ydata[:entries]        
    figure = plt.figure(figsize = (12,6), facecolor = "white")
    ax = figure.add_subplot(1,1,1)
    plt.grid(True)
    if xdata and ydata:
        ax.bar(xdata, ydata, width=barwidth,align='center',color='blue')
        ax.set_xlabel('categories',color='black')
        ax.set_ylabel('duration in  minutes',color='black')
        ax.set_title('duration plot created ')
        ax.set_xticks(xdata)
        ax.set_xticklabels(xlabels)
        figure.autofmt_xdate(rotation=30)
        plt.show()

When I tried

create_bar_plot(5)

I got this figure

But when I called

create_bar_plot(1)

I get this fat bar

So, how do I make the plot show each bar with fixed width? It seems the width=barwidth in bar() doesn't work as I expected it would.. Very likely I am missing something..

Please help

wim · Accepted Answer · 2021-04-16T16:43:52.457

2

They are actually the same bar width, it's just your x-axis scale that is different. See:

>>> create_bar_plot(5)
>>> plt.gca().get_xbound()
(-1.0, 5.0)
>>> create_bar_plot(1)
>>> plt.gca().get_xbound()
(-0.30000000000000004, 0.30000000000000004)
>>> ax = plt.gca()
>>> ax.set_xbound(-1.0 ,5.0)
>>> plt.show()

edited Apr 16 '21 at 16:43

answered Jan 17 '13 at 07:29

wim

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score 1 · Answer 2 · answered Jan 17 '13 at 07:33

The bar is still the same width, .45, but the range of the x-axis is scaled down because there is less data. You could manually set the xlim() to make both axis the same width, then the bars will also have the same width.

So:

    ax.set_xlim(-1,len(xlabels))

It wouldnt center the bar anymore, so you might need some further adjustments depending on the final result you're after.

displaying fixed width bars for all datasets in matplotlib

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