Why is code not printing the negative value in my list? The max value works fine but nothing prints for negative.

user_input = ''
user_values = []
x = 0
maxim = 0
sum = 0
avg = 0
neg_values = 0
mini = 0
while True:
    user_input = (input('input:'))
    if user_input in ['q', 'Q']:
        break

    elif user_input not in  ['q', 'Q'] and user_input.isnumeric():
        user_values.append(int(user_input))

for value in user_values:
    maxim = max(value,maxim)
print( "the maximum value in the list is : " , maxim)

Minumum_value = min(user_values)
print( "the minumum value in the list is : " , Minumum_value)

for value in user_values:
    if value < 0:
        print("the negative values are : "  ,  value)

The code should work as the user inputs value and quits when he types q. Then it should find neg values or the max etc.

CodePudding user response：

This is not doing what you expect because isnumeric() doesn't do what you think it does. Try this at a Python prompt:

>>> "-1".isnumeric()
False

To do what you want, convert the input value to int and wrap the conversion in a try...except ValueError.

try:
    user_values.append(int(user_input))
except ValueError:
    print("Invalid input", user_input, "ignored")

As a side note, this:

for value in user_values:
    maxim = max(value,maxim)

is pointless. Instead do maxim = max(user_values). You only need to calculate the maximum once. Same for the minimum.

CodePudding user response：

This is due to your isnumeric check: that isn't doing what you expect.

>>> '-3'.isnumeric()
False

The method checks is all characters are digits, the minus sign is not part of it.

You could use a try/except:

try:
    user_values.append(int(user_input))
except ValueError:
    print('invalid input')

CodePudding user response：

why don't you just use try-except?

while True:
    user_input = (input('input:'))
    if user_input in ['q', 'Q']:
        break

    elif user_input not in  ['q', 'Q'] and user_input.isnumeric():
        user_values.append(int(user_input))

Except Try this code.

while True:
    user_input = (input('input:'))
    if user_input in ['q', 'Q']:
        break
    else:
        try:
            user_values.append(int(user_input))
        except ValueError:
            print("Error log...")