Convert Pi to an approximate rational value on the various denominatorΒΆ

Convert a floating point number (pi) to an approximate rational value on the various denominator.
Note: max_denominator = 1000000
Expected output:
PI = 3.141592653589793
No limit = 3141592653589793/1000000000000000
1 = 3
5 = 16/5
50 = 22/7
90 = 267/85
100 = 311/99
500 = 355/113
1000000 = 3126535/995207
import fractions
import math

print('PI       =', math.pi)

f_pi = fractions.Fraction(str(math.pi))
print('No limit =', f_pi)

for d in [1, 5,  50, 90, 100, 500, 1000000]:
    limited = f_pi.limit_denominator(d)
    print('{0:8} = {1}'.format(d, limited))

Output:

PI       = 3.141592653589793
No limit = 3141592653589793/1000000000000000
       1 = 3
       5 = 16/5
      50 = 22/7
      90 = 267/85
     100 = 311/99
     500 = 355/113
 1000000 = 3126535/995207