python - Using isdigit for floats?

Question

a = raw_input('How much is 1 share in that company? ')

while not a.isdigit():
    print("You need to write a number!
")
    a = raw_input('How much is 1 share in that company? ')

This only works if the user enters an integer, but I want it to work even if they enter a float, but not when they enter a string.

So the user should be able to enter both 9 and 9.2, but not abc.

How should I do it?

Answer 1

EAFP

try:
    x = float(a)
except ValueError:
    print("You must enter a number")