Calculates the Passer Rating (passer efficiency or pass efficiency) of a player given some variables. Use at own risk, old-as-fuck code here.

passer_rating.py

# This Python application will calculate the passer rating
# (passer efficiency or pass efficiency) given the five required variables.
#
# Variables to be used as values are defined below. Set to strings so input
# can be anything. Later the strings will be converted to numbers, given
# they pass a series of error checking tests.

COMP = "null"
ATT = "null"
YARDS = "null"
TD = "null"
INT = "null"

# Function defined to check if string is a valid number,
# and if it is larger than zero. (Invalid if < 0

def checkIfNum(stringToTest):
  try:
    temp = float(stringToTest)
  except ValueError:
  # isn't a number
	return False
  else:
    if(temp < 0):
      return False
    else:
   	# is a number
      return True

# Get user input of the numbers, and check to make sure that the input
# is a valid number. If it's not a valid number, it will re-ask for input.

while checkIfNum(COMP) == False:
  COMP=raw_input('Enter the number of completions:')

while checkIfNum(ATT) == False:
  ATT=raw_input('Enter the number of attempts:')

while checkIfNum(YARDS) == False:
  YARDS=raw_input('Enter the total number of yards:')

while checkIfNum(TD) == False:
  TD=raw_input('Enter the number of touchdown passes:')

while checkIfNum(INT) == False:
  INT=raw_input("Enter the number of interceptions:")

# Converts all the strings to integers (already verified as valid numbers).

COMP=int(COMP)
ATT=int(ATT)
YARDS=int(YARDS)
TD=int(TD)
# INT is the name of the variable which holds the number
# of INTerceptions, int is the built in function which
# converts the strings to integers.
INT=int(INT)

# The calculations are processed here using the newly converted integers.
# The resulting calculations are easy to determine from the variable names.

completionPercentage = ((COMP/ATT*100)-30)*.05
print("Completion Percentage = %d") % (completionPercentage)

avgYardPerAttempt = ((YARDS/ATT)-3)*0.25
print("Average Yards Per Attempt = %d") % (avgYardPerAttempt)

percentOfTdPasses = (TD/ATT)*20
print("Percentage of Touchdown Passes = %d") % (percentOfTdPasses)

percentOfInt = 2.375 - (INT/ATT * 25)
print("Percentage of Interceptions = %d") % (percentOfInt)

passerRating = ((completionPercentage + avgYardPerAttempt
+ percentOfTdPasses + percentOfInt)/6)*100

# After the final Passer Rating has been calculated,
# the result is printed on screen.

print("Passer Rating = %d") % (passerRating)