Question

Wondering if there is a better way to do this. Python is my first programming language.

while True:
    amount_per_month = raw_input('\nWhat is the monthly cost?\n==> ')
    # seperate dollars and cents.
    amount_list = amount_per_month.split(".")
    # checking if int(str) is digit
    if len(amount_list) == 1 and amount_list[0].isdigit() == True:
        break
    # checking if float(str) is digit
    elif len(amount_list) == 2 and amount_list[0].isdigit() and amount_list[1].isdigit() == True:
        break
    else:
        raw_input('Only enter digits 0 - 9.  Press Enter to try again.')
        continue

Answer 1

Just try to make it a float and handle the exception thrown if it can’t be converted.

try:
    amount_per_month = float( raw_input('What is the monthly cost?') )
except (ValueError, TypeError) as e:
    pass # wasn't valid

TypeError is redundant here, but if the conversion was operating on other Python objects (not just strings), then it would be required to catch things like float( [1, 2, 3] ).