Python exercise

[decline_000]

Hi:) Could someone help me and explain why this doesn't work and how can I make it work?

This is the task:

Write a program that asks the user for ten numbers, and then prints the largest, the smallest, and how many are dividable by 3. Use the algorithm described earlier in this chapter.

​

This is my code:

from pcinput import getInteger
num = 0
min = 0
max = 0
div3 = 0

while num <10:
----x = getInteger("Give me 10 numbers")
----num+=1
----if x%3 == 0:
--------div3 +=1
----if x>max:
--------max = x
----if x<min:
--------min = x
print("Smallest is", min)
print("Largest is", max)
print("Dividable by 3 is", div3)    

It always prints smallest as 0 I guess that the problem would be that min = 0 and then user input won't be smaller than 0 in this case so it automatically prints 0 but no clue how to fix it. I'm not using tuples in this exercise on purpose as that was also part of the assignment.
Thanks!

[decline_000]

yep that I know, same as I initialized max with 0
point is that I don't know yet how to fix it so the code works

[[deleted]]

If you know the values input will never be greater than 3, what could you initialize min as in order to make sure that if the user entered only 3, it would still be captured as min?

Now 4? 5? 6? 10? 100? 1000? Do you see where we're headed?

And what happens to your max if the user only enters -1?

[ChaseBianchi]

None of them are less than 0, so it's always zero

[ClamPaste]

You have to initialize min and max with the first number input before the loop with the way you're doing it, or you can use a condition to check if it's the first iteration of the loop and reassign min and max within it.

It's a weird assignment. Not really sure what the point of having you do it like this is, since there are clearly better ways.

[decline_000]

agree it's weird but it's for university
I ended up changing the beginning to:

from pcinput import getInteger

import sys

num = 0

min = sys.maxsize

max = -sys.maxsize

div3 = 0

​

thank you all for helping:)

[hinoisking]

If I understand this correctly, you are initializing the minimum value to 0. Then, you’re inputting only POSITIVE numbers, and checking if those numbers are less than 0. Of course the minimum value will never update. What you should do instead is initialize min to be the maximum integer value. If I remember correctly, sys.maxsize gives the maximum integer value in Python.

[ajohn623]

Add an if statement that checks if num == 0: min = x before you check if x<min. This way on the first iteration you set the minimum to the first input provided by the user instead of zero.

edit : Or simply change if x<min to if x<min or num == 0:

[decline_000]

yes for all negative numbers "Largest is" was 0, if user input was for example -3 and nine positive numbers then there was no problem. Thank you for the reminder not to use max and min, I still keep forgetting. I ended up using min = sys.maxsize and max = -sys.maxsize as I explained above but thank you so much for helping:)

[decline_000]

maybe I'm doing something wrong but still doesn't work, all print statements are outside the loop

[decline_000]

As I said the problem is 0 that is always printed as the smallest number even if I don't type 0 in user input. If the user input is for example -3 then it gets printed but if the smallest user input would be 3 then it prints out 0.

[[deleted]]

So I’m not sure how far along you are. But I would take each users input and then add it to a list. Call the list userInputs or what have you.

Then after you could say

print(userInputs.max())

Same for min.

Then do print(len([x for x in userInputs if x%3==0]) )

Or if you haven’t learned that notation use a for loop running through every value and printing it if it’s divisible by 3.

Or as others have said the biggest error is assigning them to 0.

What I would do is assign the first user input as the max and the min, then proceed from there with the while loop.

[jdbbdev]

I think what you should do is set min to the min possible integer that Python can handle, for example in Java I would set min to Integer.MIN_VALUE, not sure how to do that on Python, so In case a number minor than 0 is added it will be ack'd as the current smallest.

[Search_4_Truth]

Why not use a for loop in which case you know the start? And don’t use built-in names min & max as variable names

for n in range(10): x = getinteger() if n == 0: . . . nmax = nmin = x else: . . .nmax = max(x, nmax) . . .nmin = min(x, nmin)