Histogram from Table

Hi, I'm trying to make a histogram with above table, and below is my coding.

def histograms(t):
    salaries = t.column('Salary')
    salary_bins = np.arange(min(salaries), max(salaries)+1000, 1000)
    t.hist('Salary', bins=salary_bins, unit='$')
    
histograms(full_data)

But it's not showing properly. Can you help me?

Histogram

Solution

The bins argument in a histogram specifies the number of bins into which the data will be evenly distributed.

Let's say you have a sample dataframe of salaries like this:

import pandas as pd

sample_dataframe = pd.DataFrame({'name':['joe','jill','martin','emily','frank','john','sue','sally','sam'],
                                 'salary':[105324,65002,98314,24480,55000,62000,75000,79000,32000]})

#output:
     name  salary
0     joe  105324
1    jill   65002
2  martin   98314
3   emily   24480
4   frank   55000
5    john   62000
6     sue   75000
7   sally   79000
8     sam   32000

If you want to plot a histogram where the salaries will be distributed in 10 bins and you want to stick with your function, you can do:

import matplotlib.pyplot as plt

def histograms(t):
    plt.hist(t.salary, bins = 10, color = 'orange', edgecolor = 'black')
    plt.xlabel('Salary')
    plt.ylabel('Count')
    plt.show()

histograms(sample_dataframe)

If you want the x-axis ticks to reflect the boundaries of the 10 bins, you can add this line:

import numpy as np
plt.xticks(np.linspace(min(t.salary), max(t.salary), 11), rotation = 45)

Finally to show the y-ticks as integers, you add these lines:

from matplotlib.ticker import MaxNLocator
plt.gca().yaxis.set_major_locator(MaxNLocator(integer=True))

The final function looks like this:

def histograms(t):
    plt.hist(t.salary, bins = 10, color = 'orange', edgecolor = 'black')
    plt.xlabel('Salary')
    plt.ylabel('Count')

    plt.gca().yaxis.set_major_locator(MaxNLocator(integer=True))
    plt.xticks(np.linspace(min(t.salary), max(t.salary), 11), rotation = 45)
    plt.show()