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












0















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()









share|improve this question

























  • What is your issue exactly? One issue is If 0 and 1 aren't in the data, it won't be the bins you expect. You'll want to explicitly define your bins (or range) since they will be determined by the min and max of your data.

    – busybear
    Nov 21 '18 at 1:15













  • In case you want to use a bar plot, see e.g. this answer.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 2:05
















0















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()









share|improve this question

























  • What is your issue exactly? One issue is If 0 and 1 aren't in the data, it won't be the bins you expect. You'll want to explicitly define your bins (or range) since they will be determined by the min and max of your data.

    – busybear
    Nov 21 '18 at 1:15













  • In case you want to use a bar plot, see e.g. this answer.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 2:05














0












0








0








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()









share|improve this question
















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()






python arrays numpy matplotlib histogram






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share|improve this question













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edited Nov 21 '18 at 1:10









eyllanesc

80.6k103258




80.6k103258










asked Nov 21 '18 at 1:10









JacobJacob

44324




44324













  • What is your issue exactly? One issue is If 0 and 1 aren't in the data, it won't be the bins you expect. You'll want to explicitly define your bins (or range) since they will be determined by the min and max of your data.

    – busybear
    Nov 21 '18 at 1:15













  • In case you want to use a bar plot, see e.g. this answer.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 2:05



















  • What is your issue exactly? One issue is If 0 and 1 aren't in the data, it won't be the bins you expect. You'll want to explicitly define your bins (or range) since they will be determined by the min and max of your data.

    – busybear
    Nov 21 '18 at 1:15













  • In case you want to use a bar plot, see e.g. this answer.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 2:05

















What is your issue exactly? One issue is If 0 and 1 aren't in the data, it won't be the bins you expect. You'll want to explicitly define your bins (or range) since they will be determined by the min and max of your data.

– busybear
Nov 21 '18 at 1:15







What is your issue exactly? One issue is If 0 and 1 aren't in the data, it won't be the bins you expect. You'll want to explicitly define your bins (or range) since they will be determined by the min and max of your data.

– busybear
Nov 21 '18 at 1:15















In case you want to use a bar plot, see e.g. this answer.

– ImportanceOfBeingErnest
Nov 21 '18 at 2:05





In case you want to use a bar plot, see e.g. this answer.

– ImportanceOfBeingErnest
Nov 21 '18 at 2:05












2 Answers
2






active

oldest

votes


















3














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



With your sample array the code would look like:



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


enter image description here






share|improve this answer
























  • I don't want to specify the number of bins because the number of bins is variable, in this example I only have 5 but I could 30, or 40, or 1000. The graph in this picture is an example of what I want, but I might have 5 graphs like this beside eachother, so ideally I want each array index of y to be a bar

    – Jacob
    Nov 21 '18 at 12:37











  • Ignore everything after the last comma in my last sentence

    – Jacob
    Nov 21 '18 at 12:48



















-1














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()





share|improve this answer





















  • 1





    Attention! this only looks like it's working correctly. And that only by coincidence. You will need to define the bins as in the other answer.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 1:53













  • What do you mean ? The call to histogram() gives back 5 values as per bins=5, and the call to bar() specifies the location of the center of the bins (through x and the default keyword align='center') as well as their total width. I agree hist() does the job way better (and I have upvoted the answer), but I do not see why my answer would be only coincidentally working ? I just used and improved the snippet provided by the OP.

    – Patol75
    Nov 21 '18 at 4:42






  • 1





    If you take 100 random points between 0 and 1 and put them into 5 bins, the likelyhood is pretty high that those bins are close to [0,0.2), [0.2,0.4), etc. However, it is an assumption which is in general not true, and will lead to wrong results if you took e.g. the data provided in the question. Your approach would then give this result, which is obviously different from @user7374610's result and you may easily count the values by hand to see that it's not correctly binning the values.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 4:57











  • Ah, yes, makes sense now, thank you.

    – Patol75
    Nov 21 '18 at 5:00











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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes









3














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



With your sample array the code would look like:



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


enter image description here






share|improve this answer
























  • I don't want to specify the number of bins because the number of bins is variable, in this example I only have 5 but I could 30, or 40, or 1000. The graph in this picture is an example of what I want, but I might have 5 graphs like this beside eachother, so ideally I want each array index of y to be a bar

    – Jacob
    Nov 21 '18 at 12:37











  • Ignore everything after the last comma in my last sentence

    – Jacob
    Nov 21 '18 at 12:48
















3














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



With your sample array the code would look like:



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


enter image description here






share|improve this answer
























  • I don't want to specify the number of bins because the number of bins is variable, in this example I only have 5 but I could 30, or 40, or 1000. The graph in this picture is an example of what I want, but I might have 5 graphs like this beside eachother, so ideally I want each array index of y to be a bar

    – Jacob
    Nov 21 '18 at 12:37











  • Ignore everything after the last comma in my last sentence

    – Jacob
    Nov 21 '18 at 12:48














3












3








3







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



With your sample array the code would look like:



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


enter image description here






share|improve this answer













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



With your sample array the code would look like:



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


enter image description here







share|improve this answer












share|improve this answer



share|improve this answer










answered Nov 21 '18 at 1:32









zrelovazrelova

7181522




7181522













  • I don't want to specify the number of bins because the number of bins is variable, in this example I only have 5 but I could 30, or 40, or 1000. The graph in this picture is an example of what I want, but I might have 5 graphs like this beside eachother, so ideally I want each array index of y to be a bar

    – Jacob
    Nov 21 '18 at 12:37











  • Ignore everything after the last comma in my last sentence

    – Jacob
    Nov 21 '18 at 12:48



















  • I don't want to specify the number of bins because the number of bins is variable, in this example I only have 5 but I could 30, or 40, or 1000. The graph in this picture is an example of what I want, but I might have 5 graphs like this beside eachother, so ideally I want each array index of y to be a bar

    – Jacob
    Nov 21 '18 at 12:37











  • Ignore everything after the last comma in my last sentence

    – Jacob
    Nov 21 '18 at 12:48

















I don't want to specify the number of bins because the number of bins is variable, in this example I only have 5 but I could 30, or 40, or 1000. The graph in this picture is an example of what I want, but I might have 5 graphs like this beside eachother, so ideally I want each array index of y to be a bar

– Jacob
Nov 21 '18 at 12:37





I don't want to specify the number of bins because the number of bins is variable, in this example I only have 5 but I could 30, or 40, or 1000. The graph in this picture is an example of what I want, but I might have 5 graphs like this beside eachother, so ideally I want each array index of y to be a bar

– Jacob
Nov 21 '18 at 12:37













Ignore everything after the last comma in my last sentence

– Jacob
Nov 21 '18 at 12:48





Ignore everything after the last comma in my last sentence

– Jacob
Nov 21 '18 at 12:48













-1














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()





share|improve this answer





















  • 1





    Attention! this only looks like it's working correctly. And that only by coincidence. You will need to define the bins as in the other answer.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 1:53













  • What do you mean ? The call to histogram() gives back 5 values as per bins=5, and the call to bar() specifies the location of the center of the bins (through x and the default keyword align='center') as well as their total width. I agree hist() does the job way better (and I have upvoted the answer), but I do not see why my answer would be only coincidentally working ? I just used and improved the snippet provided by the OP.

    – Patol75
    Nov 21 '18 at 4:42






  • 1





    If you take 100 random points between 0 and 1 and put them into 5 bins, the likelyhood is pretty high that those bins are close to [0,0.2), [0.2,0.4), etc. However, it is an assumption which is in general not true, and will lead to wrong results if you took e.g. the data provided in the question. Your approach would then give this result, which is obviously different from @user7374610's result and you may easily count the values by hand to see that it's not correctly binning the values.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 4:57











  • Ah, yes, makes sense now, thank you.

    – Patol75
    Nov 21 '18 at 5:00
















-1














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()





share|improve this answer





















  • 1





    Attention! this only looks like it's working correctly. And that only by coincidence. You will need to define the bins as in the other answer.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 1:53













  • What do you mean ? The call to histogram() gives back 5 values as per bins=5, and the call to bar() specifies the location of the center of the bins (through x and the default keyword align='center') as well as their total width. I agree hist() does the job way better (and I have upvoted the answer), but I do not see why my answer would be only coincidentally working ? I just used and improved the snippet provided by the OP.

    – Patol75
    Nov 21 '18 at 4:42






  • 1





    If you take 100 random points between 0 and 1 and put them into 5 bins, the likelyhood is pretty high that those bins are close to [0,0.2), [0.2,0.4), etc. However, it is an assumption which is in general not true, and will lead to wrong results if you took e.g. the data provided in the question. Your approach would then give this result, which is obviously different from @user7374610's result and you may easily count the values by hand to see that it's not correctly binning the values.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 4:57











  • Ah, yes, makes sense now, thank you.

    – Patol75
    Nov 21 '18 at 5:00














-1












-1








-1







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()





share|improve this answer















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()






share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 21 '18 at 5:05

























answered Nov 21 '18 at 1:33









Patol75Patol75

6236




6236








  • 1





    Attention! this only looks like it's working correctly. And that only by coincidence. You will need to define the bins as in the other answer.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 1:53













  • What do you mean ? The call to histogram() gives back 5 values as per bins=5, and the call to bar() specifies the location of the center of the bins (through x and the default keyword align='center') as well as their total width. I agree hist() does the job way better (and I have upvoted the answer), but I do not see why my answer would be only coincidentally working ? I just used and improved the snippet provided by the OP.

    – Patol75
    Nov 21 '18 at 4:42






  • 1





    If you take 100 random points between 0 and 1 and put them into 5 bins, the likelyhood is pretty high that those bins are close to [0,0.2), [0.2,0.4), etc. However, it is an assumption which is in general not true, and will lead to wrong results if you took e.g. the data provided in the question. Your approach would then give this result, which is obviously different from @user7374610's result and you may easily count the values by hand to see that it's not correctly binning the values.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 4:57











  • Ah, yes, makes sense now, thank you.

    – Patol75
    Nov 21 '18 at 5:00














  • 1





    Attention! this only looks like it's working correctly. And that only by coincidence. You will need to define the bins as in the other answer.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 1:53













  • What do you mean ? The call to histogram() gives back 5 values as per bins=5, and the call to bar() specifies the location of the center of the bins (through x and the default keyword align='center') as well as their total width. I agree hist() does the job way better (and I have upvoted the answer), but I do not see why my answer would be only coincidentally working ? I just used and improved the snippet provided by the OP.

    – Patol75
    Nov 21 '18 at 4:42






  • 1





    If you take 100 random points between 0 and 1 and put them into 5 bins, the likelyhood is pretty high that those bins are close to [0,0.2), [0.2,0.4), etc. However, it is an assumption which is in general not true, and will lead to wrong results if you took e.g. the data provided in the question. Your approach would then give this result, which is obviously different from @user7374610's result and you may easily count the values by hand to see that it's not correctly binning the values.

    – ImportanceOfBeingErnest
    Nov 21 '18 at 4:57











  • Ah, yes, makes sense now, thank you.

    – Patol75
    Nov 21 '18 at 5:00








1




1





Attention! this only looks like it's working correctly. And that only by coincidence. You will need to define the bins as in the other answer.

– ImportanceOfBeingErnest
Nov 21 '18 at 1:53







Attention! this only looks like it's working correctly. And that only by coincidence. You will need to define the bins as in the other answer.

– ImportanceOfBeingErnest
Nov 21 '18 at 1:53















What do you mean ? The call to histogram() gives back 5 values as per bins=5, and the call to bar() specifies the location of the center of the bins (through x and the default keyword align='center') as well as their total width. I agree hist() does the job way better (and I have upvoted the answer), but I do not see why my answer would be only coincidentally working ? I just used and improved the snippet provided by the OP.

– Patol75
Nov 21 '18 at 4:42





What do you mean ? The call to histogram() gives back 5 values as per bins=5, and the call to bar() specifies the location of the center of the bins (through x and the default keyword align='center') as well as their total width. I agree hist() does the job way better (and I have upvoted the answer), but I do not see why my answer would be only coincidentally working ? I just used and improved the snippet provided by the OP.

– Patol75
Nov 21 '18 at 4:42




1




1





If you take 100 random points between 0 and 1 and put them into 5 bins, the likelyhood is pretty high that those bins are close to [0,0.2), [0.2,0.4), etc. However, it is an assumption which is in general not true, and will lead to wrong results if you took e.g. the data provided in the question. Your approach would then give this result, which is obviously different from @user7374610's result and you may easily count the values by hand to see that it's not correctly binning the values.

– ImportanceOfBeingErnest
Nov 21 '18 at 4:57





If you take 100 random points between 0 and 1 and put them into 5 bins, the likelyhood is pretty high that those bins are close to [0,0.2), [0.2,0.4), etc. However, it is an assumption which is in general not true, and will lead to wrong results if you took e.g. the data provided in the question. Your approach would then give this result, which is obviously different from @user7374610's result and you may easily count the values by hand to see that it's not correctly binning the values.

– ImportanceOfBeingErnest
Nov 21 '18 at 4:57













Ah, yes, makes sense now, thank you.

– Patol75
Nov 21 '18 at 5:00





Ah, yes, makes sense now, thank you.

– Patol75
Nov 21 '18 at 5:00


















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