CODEWITHSUNDEEP
pythonarraysnumpymatplotlibhistogram
Sam
Sam

Reputation: 2331

Creating a histogram that sorts array values into bins, and shows the the frequency of items in the bins

For an array of values between 0 and 1, I want to create a histogram of 5 bins where bin one show the frequency(# of times) numbers between 0-0.2 show up in the array, bin 2 shows the frequency of numbers between 0.2-0.4, bin 3 is 0.4-0.6, bin 4: 0.6-0.8, bin 5 0.8-1.

import numpy as np
arr = np.array([0.5, 0.1, 0.05, 0.67, 0.8, 0.9, 1, 0.22, 0.25])
y, other_stuff = np.histogram(arr, bins=5)
x = range(0,5)
graph = plt.bar(x,height=y)
plt.show()

Upvotes: 0

Views: 2010

Answers (2)

Zito Relova
Zito Relova

Reputation: 1041

I think you are looking for matplotlib's hist method.

With your sample array the code would look like: 

import matplotlib.pyplot as plt

plt.hist(arr, bins=np.linspace(0,1,6), ec='black')

enter image description here

Upvotes: 3

Patol75
Patol75

Reputation: 4547

Is it what you are after ?

import numpy
from numpy.random import random
import matplotlib.pyplot as plt
arr = random(100)
y, other_stuff = numpy.histogram(arr, bins=5)
x = numpy.linspace(0.1, 0.9, 5)
graph = plt.bar(x, height=y, width=0.2, edgecolor='black')
plt.show()

As pointed out in the comment below, the snippet above does not define the edges of the bins in the call to histogram(). The one below corrects for that.

import numpy
import matplotlib.pyplot as plt
arr = numpy.array([0.5, 0.1, 0.05, 0.67, 0.8, 0.9, 1, 0.22, 0.25])
y, other_stuff = numpy.histogram(arr, bins=numpy.linspace(0, 1, 6))
graph = plt.bar(numpy.linspace(0.1, 0.9, 5), height=y, width=0.2,
                edgecolor='black')
plt.show()

Upvotes: -2

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