I have a list of numbers.The list is like [0,0,1,0,1 .... ] .Presently it has binary digits only but later on it can have decimal digits as well. I want to plot a histogram of this sequence in the list.
When I use standard hist funcion of matplotlib library , I get only two bars.It counts all zeros and all ones and shows me the histogram with two bars. But I want to plot in a different way.
I want a no of bars = length of list
and
Height of each bar = value in the list at ( position = bar# ).
Here is the code:
def plot_histogram(self,li_input,):
binseq = numpy.arange(len(li_input))
tupl = matplotlib.pyplot.hist(li_input,bins=binseq)
matplotlib.pyplot.show()
li_input is the list discussed above.
I can do it in a nasty way like :
li_input_mod = []
for x in range(len(li_input)):
li_input_mod += [x]*li_input[x]
and then plot it but i want something better.
The behavior you describe is the way a histogram works; it shows you the distribution of values. It sounds to me like you want to create a bar chart:
import matplotlib.pyplot as plt
x = [0,0,1,0,1,1,0,1,1,0,0,0,1]
plt.bar(range(len(x)), x, align='center')
which would produce:
Related
For an assignment in class, I made a number generator that writes the output into a file. I need to read this file and make a histogram showing how many values are in specific ranges like 0-9, 10-19, 20-29, etc. The problem I'm running into is that I can't change the x-values on the bottom of the graph. I want it to be the same as 0-9, 10-19, etc but I can't find anything online that'll let me change it to that.
This is my code
import os
from matplotlib import pyplot as plt
os.chdir("/Users/elian/Desktop/School/Scripting/Week 7")
with open("Random.txt", "r") as file:
values = file.read()
contents = values.split()
mapped_contents = map(int, contents)
contents = list(mapped_contents)
file.close()
# histogram = plt.hist(contents, bins=binset, )
plt.hist(contents, bins=10)
plt.ylabel("Amount")
plt.xlabel("Range")
plt.title("Random Number Generator Histogram")
plt.show()
This is my first time working with matplotlib so I apologize if I'm not explaining everything right. I just want the histogram to show the amount of numbers that are in a specific range. I've tried range and xlim but I still run into the problem where the x-axis increments in 20s.
The command for placing values on the axis is plt.xticks(ticks, labels). However, in case of a histogram, the values are automatically arranged as per the data and bin size. So if you change the bin size, you would be able to see the values accordingly.
You can specify the x values in the bins parameter itself by passing a list of the values.
Example:
plt.hist(data, bins=[1, 2, 3, 4, 5])
The histogram would look as given in the link below.
histogram
I've generated a lot of numbers using Python, saving them in a list, and now I want to plot them in a scatter graph and a bar graph to see the patterns of the function that I created.
I'm getting numbers from 0 to 99,999,999 at maximum, I tried to plot but I failed.
In the bar graph the y axis should show how many times a number repeated itself in the range of the numbers generated and the x axis the number itself.
I tried to use the method collections.counter but it keeps returning me a dict with all the numbers that appeard at least one time in the list, instead of the ones that just repeated, with the data of the numbers that repeated I think I could plot the graph properly.
Image showing the data that i get from the function
What would you like to plot in the scatter graph? Matplotlib has built-in histogram plotter.
import random
import matplotlib.pyplot as plt
random.seed(0)
ITER = 20
LOW = 0
HIGH = 10
RND_NUMS = []
for _ in range(ITER):
RND_NUMS.append(random.randint(LOW, HIGH))
plt.hist(RND_NUMS, bins=range(0,10))
This produces something like:
I am making a basic program using matplotlib which graphs a large number of points, and calculates a value to colour those points. My issue is that as the number of points gets very large, the time it takes to individually plot each point through a for loop also gets very large. Is there any way I can use one plot statement and specify a list to use the colours for each individual point? As an example,
Current method:
colours = [(1,0,0),(0,1,0),(0,1,1)] #The length of these lists is usual in the thousands
x = [0,1,2]
y = [2,1,0]
for i in range(len(colours)):
plot([x[i]],[y[i]],'o', color = colours[i])
Whereas what I would like to use would be something more like:
plot(x,y,'o', color=colours)
Which would use each colour for each point. Is there any better way to approach this than a for loop?
You do not want to use plot, but scatter.
import matplotlib.pyplot as plt
colours = [(1,0,0),(0,1,0),(0,1,1)]
x = [0,1,2]
y = [2,1,0]
plt.scatter(x,y, c=colours)
plt.show()
I am struggling wth plotting a histogram with two lists through the pylab module (which I am required to use)
The first list, totalTime, is populated with 7 float values calculated within the program.
The second list, raceTrack, is populated with 7 string values that represent the name of a race track.
totalTime[0] is the time taken on raceTrack[0], totalTime[3] is the time taken on raceTrack[3], etc...
I sorted out the array and rounded the values to 2 decimal place
totalTimes.sort()
myFormattedTotalTimes = ['%.2f' % elem for elem in totalTimes]
myFormattedTotalTimes' output (when the value entered is 100) is
['68.17', '71.43', '71.53', '84.23', '84.55', '87.20', '102.85']
I would need to use the values in the list to create a histogram, where x-axis would show the name of the race track and the y-axis would show the time on that particular track. Ive made quickly an excel histogram to help understand.
I have attempted but to no avail
for i in range (7):
pylab.hist([myFormattedTotalTimes[i]],7,[0,120])
pylab.show()
Any help would be very appreciated, I am quite lost on this one.
As #John Doe states, I think you want a bar chart. From the matplotlib example, the following does what you want,
import matplotlib.pyplot as plt
import numpy as np
myFormattedTotalTimes = ['68.17', '71.43', '71.53', '84.23', '84.55', '87.20', '102.85']
#Setup track names
raceTrack = ["track " + str(i+1) for i in range(7)]
#Convert to float
racetime = [float(i) for i in myFormattedTotalTimes]
#Plot a bar chart (not a histogram)
width = 0.35 # the width of the bars
ind = np.arange(7) #Bar indices
fig, ax = plt.subplots(1,1)
ax.bar(ind,racetime, width)
ax.set_xticks(ind + width)
ax.set_xticklabels(raceTrack)
plt.show()
Which looks like,
I have an histogram like this:
Where my data are stored with an append in that way:
(while parsing the file)
{
[...]
a.append(int(number))
#a = [1,1,2,1,1, ]...
}
plt.hist(a, 180)
But as you can see from the image, there are lot of blank areas, so I would like to build a barchart from this data, how can I reorganize them like:
#a = [ 1: 4023, 2: 3043, 3:...]
Where 1 is the "number" and 4023 is an example on how many "hit" of the number 1? From what I have seen in this way I can call:
plt.bar(...)
and creating it, so that I can show only the relevant numbers, with more readability.
If there is a simple way to cut white area in the Histo is also welcome.
I would like also to show the top counter of each columns, but I have no idea how to do it.
Assuming you have some numpy array a full of integers then the code below will produce the bar chart you desire.
It uses np.bincount to count the number of values, note that it only works for non-negative integers.
Also note that I have adjusted the indices so that the plot centrally rather than to the left (using ind-width/2.).
import matplotlib.pyplot as plt
import numpy as np
# Generate some random data.
N=300
a = np.random.random_integers(low=0, high=20, size=N)
# Use bincount and nonzero to generate your data in the correct format.
b = np.bincount(a)
ind = np.nonzero(b)[0]
width=0.8
fig, ax = plt.subplots()
ax.bar(ind-width/2., b)
plt.show()