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List conversion and multiplication - Printable Version

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List conversion and multiplication - johnkyp - Dec-25-2019

Hello,

I am trying to work my way through some practice exercises where the objective is to convert a string containing numbers, so that I am able to multiply those numbers to each other. A key requirement is that whenever there is a zero that number gets skipped.

For example, if I have the string “123405”, the multiplication would look like this: 1*2*3*4*5 yielding 120.

My problem isn’t so much the if statement, as much as how to convert the string to an integer or float and then parse this to a series of numbers that I can multiply.

Could you please provide pointers or suggestions on how to approach this problem?

Thank you!

RE: List conversion and multiplication - ichabod801 - Dec-25-2019

list('123405') would give you a list of the individual characters in the list. You could then use a for loop, convert each character to an integer with the int() built-in, and multiply it (if it's not zero).

RE: List conversion and multiplication - johnkyp - Dec-25-2019

Thank you that answered my question perfectly.

Wishing you all the best for the holidays and new year!

RE: List conversion and multiplication - ndc85430 - Dec-27-2019

You don't need to create the list, since strings are also sequences. That means you can iterate over them directly:

>>> for c in "foo":
...     print(c)
... 
f
o
o
>>>


RE: List conversion and multiplication - johnkyp - Jan-01-2020

Thank you for responding. That makes sense. Also my question has been answered so I will be closing this thread. Btw, happy new year!

RE: List conversion and multiplication - perfringo - Jan-02-2020

Starting from Python 3.8 there is prod function in built-in math module.

>>> import math
>>> s = '123405'
>>> nums = (int(num) for num in s if num != '0')  
>>> math.prod(nums)
120
In code above nums is generator expression and generators will exhaust after first usage.