Python - Converting strin to Int for comarison within a function

Question

I'm taking an online class and there are assignments. The on i'm working now has me comparing 3 numbers together to look for a match. Works fine with int's but when I pass a "two" into the function instead of a 2, i'm not able to compare and if I try to convert it, i'm not able to either.

Any ideas?

boolHomework = homework3Bonus(1,2,"two")

def homework3Bonus(a,b,c):
    print("The type of input is", type(c))
    strA = a
    strB = b
    strC = int(c)  #this isn't working
    print("The type of input is", type(a))
    print("The strings are",strA,strB,strC)
    if (strA == strB) or (strB == strC) or (strA == strC):
        print("Match")

This gives the error strC = int(c) ValueError: invalid literal for int() with base 10: 'two'

Answer 1

If you want a functional way to do it, which also looks for words up to 10, this solution will work.

It allows for int values 5 ints as a string '5' or word representations 'five' to be compared.

We apply map to all the incoming values to convert them to int where possible.

Then map a lambda over each combination of pairs in the list which compares and returns True or False for each combination. itertools is a python standard library.

any then checks if any value in our resulting list is True

import itertools

NUMBER_MAP = {
    'one': 1,
    'two': 2,
    'three': 3,
    'four': 4,
    'five': 5,
    'six': 6,
    'seven': 7,
    'eight': 8,
    'nine': 9,
    'ten': 10
}


def to_int(val):
    if isinstance(val, str):
        try:
            # convert number in string to int, e.g '2', '5', etc
            val = int(val)
        except ValueError:
            # convert work representation to int
            val = NUMBER_MAP.get(val.lower(), val)
    return val


def homework3Bonus(a, b, c):

    if any(map(lambda x: x[0] == x[1], itertools.combinations(map(to_int, (a, b, c)), 2))):
        print('Match')


homework3Bonus(3, 2, 'three')
homework3Bonus(3, 2, '3')
homework3Bonus(3, 2, 'two')

This could then easily be extended to take any number of arguments to find a match in an abitrary length of values.

def homework3Bonus(*args):

    if any(map(lambda x: x[0] == x[1], itertools.combinations(map(to_int, args), 2))):
        print('Match')


homework3Bonus(3, 2, 1, 5, '6', 'three')

Answer 2

Try this if you have low contraints for which it is possible to write a list stralpha manually as given below:

def homework3Bonus(a,b,c):
    a, b, c = str(a), str(b), str(c)
    lst = [a, b, c]
    
    max_possible = 10
    strnum = [str(i) for i in range(max_possible)]
    stralpha = ["zero", "one", "two", three", "four", "five", "six", "seven", "eight", "nine"]
    
    for i in range(3):
        if lst[i].isalpha():
            lst[i] = strnum[stralpha.index[lst[i].lower()]]

    return len(set(lst)) == 1
            

boolHomework = homework3Bonus(1, 2, "two")        # False
boolHomework = homework3Bonus("2", 2, "two")      # True

If you have higher contraints, you should refer to this: Is there a way to convert number words to Integers?