The following are the pandas dataframe and the bar chart generated from it:
colors_list = ['#5cb85c','#5bc0de','#d9534f'] result.plot(kind='bar',figsize=(15,4),width = 0.8,color = colors_list,edgecolor=None) plt.legend(labels=result.columns,fontsize= 14) plt.title("Percentage of Respondents' Interest in Data Science Areas",fontsize= 16) plt.xticks(fontsize=14) for spine in plt.gca().spines.values(): spine.set_visible(False) plt.yticks([])
I need to display the percentages of each interest category for the respective subject above their corresponding bar. I can create a list with the percentages, but I don’t understand how to add it on top of the corresponding bar.
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Answer
Try adding the following for
loop to your code:
ax = result.plot(kind='bar', figsize=(15,4), width=0.8, color=colors_list, edgecolor=None) for p in ax.patches: width = p.get_width() height = p.get_height() x, y = p.get_xy() ax.annotate(f'{height}', (x + width/2, y + height*1.02), ha='center')
Explanation
In general, you use Axes.annotate
to add annotations to your plots.
This method takes the text
value of the annotation and the xy
coords on which to place the annotation.
In a barplot, each “bar” is represented by a patch.Rectangle
and each of these rectangles has the attributes width
, height
and the xy
coords of the lower left corner of the rectangle, all of which can be obtained with the methods patch.get_width
, patch.get_height
and patch.get_xy
respectively.
Putting this all together, the solution is to loop through each patch in your Axes
, and set the annotation text to be the height
of that patch, with an appropriate xy
position that’s just above the centre of the patch – calculated from it’s height, width and xy coords.
For your specific need to annotate with the percentages, I would first normalize your DataFrame
and plot that instead.
colors_list = ['#5cb85c','#5bc0de','#d9534f'] # Normalize result result_pct = result.div(result.sum(1), axis=0) ax = result_pct.plot(kind='bar',figsize=(15,4),width = 0.8,color = colors_list,edgecolor=None) plt.legend(labels=result.columns,fontsize= 14) plt.title("Percentage of Respondents' Interest in Data Science Areas",fontsize= 16) plt.xticks(fontsize=14) for spine in plt.gca().spines.values(): spine.set_visible(False) plt.yticks([]) # Add this loop to add the annotations for p in ax.patches: width = p.get_width() height = p.get_height() x, y = p.get_xy() ax.annotate(f'{height:.0%}', (x + width/2, y + height*1.02), ha='center')