How to enter π in python

π in python is the math.pi variable. It is included in the standard library, and before you try to calculate it yourself, you should first import the math library and call the math.pi method.

Related recommendations: "Python Basic Tutorial"

Let us look at a very straightforward method of calculating Pi. Taking Python 2.7 as an example, the code is as follows:

import sys
import math
  
defmain(argv):  
    if len(argv) !=1:
        sys.exit(&#39;Usage: calc_pi.py <n>&#39;)  
    print&#39;\nComputing Pi v.01\n&#39;
      
    a=1.0
    b=1.0/math.sqrt(2)
    t=1.0/4.0
    p=1.0
          
    for i in range(int(sys.argv[1])):
        at=(a+b)/2
        bt=math.sqrt(a*b)
        tt=t-p*(a-at)**2
        pt=2*p          
        a=at;b=bt;t=tt;p=pt          
    my_pi=(a+b)**2/(4*t)
    accuracy=100*(math.pi-my_pi)/my_pi
          
    print"Pi is approximately: "+str(my_pi)
    print"Accuracy with math.pi: "+str(accuracy)
      
if__name__=="__main__":
    main(sys.argv[1:])

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