Whenever I go to subtract using more than 2 numbers it only does the first 2 and doesn’t use the final number. How do I fix it?

Question

My code is something I copy/pasted here since I’m looking for help
https://code.sololearn.com/cpTF1bMet8vN/?ref=app

Answer 1

Gilgames h , this is a nice try from you for a calculator. but there is an issue with your conditions in if and elif clause. Just to give you a hint how you can solve that: You have to use a parenthesis to group the statement. Do this in all 3 parts of the statement.

....
if amount==2 and (math=="subtract" or "SUBTRACT" or "Subtract"):
subtract=list[0] - list[1]#subtracts 2 numbers
print(subtract)
....

In general you should try to reduce some duplicating code. Here are some hints:

- try to use a shorter input instead of "subtract". Nobody will like to input this long word. Use "sub" or better "-"
- when you are keeping input as a word, then convert it to lower, and check against a lower word:
if amount==2 and math.lower() =="sub":
- for the calculation you should not use a hard-coded 2,3 or 4 number case. Use a for loop to do the calculation for all members in the list, you don't have to care about how many members are in the list.

happy coding!

Answer 2

here is my way to do calculation using eval() :
WARNING : it is harmful to use eval() on input() because when you use modules such as os, subprocess in your program
user can use commands such as "rm - rf *" it will delete all files and directories..

this is safe code 👇😊 :

https://code.sololearn.com/c16vh5ryLL3N/?ref=app

Answer 3

As I see you wrote ' if amount == 2 and math == "subtract" or "Subtract" or "SUBTRACT" '

It should be ' if (amount == 2) and (math == "subtract" or math == "Subtract" or math == "SUBTRACT") '
But, you can simply do ' if amount == 2 and math.lower() == "subtract" '

I don't if this will solve your problem but it will make it better

Answer 4

Gilgames h

you are using list (reserved keyword) as your variable name.. don't use it.. learn the basic of python)

you write your condition like 👇 this :

if amount==2 and math=="subtract" or "SUBTRACT" or "Subtract":

actually this is not good practice in python

simply you can use str.lower() to convert the user input in lowercase and then use it in your if condition.

Example :

math=input().lower() #SubtRaCT

if math=="subtract":
print("subtracting")

#output : subtracting

str.lower() function takes every character in a string and converts to its lowercase equivalent.

I am unable to figure it out why your code is not working... 🤔

Here is your working code :
https://code.sololearn.com/cyhGSC7K0fWx/?ref=app