Draw a histogram with Python

Calculation frequency:

Given a sequence T:

hist = {}

For x in T:

HIST[X] = Hist.get (x,0) +1

The result is a dictionary that maps the value to its frequency. Divide it by N to convert the frequency into frequencies, which is called normalization:

n = float (len (t))

PMF = {}

For X, freq in Hist.items ():

PMF[X] = freq/n

To draw a histogram:

Vals, Freqs = Hist. Render ()

rectangles = Pyplot.bar (Vals, Freqs)

Pyplot.show ()

To draw the probability mass function:

Using a histogram, you can use Pyplot.bar or myplot.hist. If the values in the PMF are not many, the histogram is more appropriate

Using a line chart, you can use Pyplot.plot or MYPLOT.PMF. If the values in the PMF are larger and smoother, the line chart is more appropriate.

* Percent Variance Chart

Visual display of the two sets of data distribution differences, see the textbook.

From statistical thinking-Programmer's mathematical probability statistics p15-p23

Draw a histogram with Python