Finding minimum of the input numbers

Question

small = None
larg = None
count = 0

while True:
    inp = raw_input("Enter a number: ")
    if inp == "done" : break

    try:
        num = float (inp)

    except:
        print "Invalid number"

    if num < small:
        small = num

print "Done"
print small

This code should make user add numbers until he/she types "done" and then find the smallest number (my idea is to compare num with small each time and it print last small value after done)

But when I run it, it keep showing None as the smallest value.

Maybe it's better to let user type all numbers and then show smallest? — Dmitry.Samborskyi, Jul 10 '15 at 06:00

score 2 · Accepted Answer · answered Jul 10 '15 at 06:01

In Python 2.x , None is smaller than all numbers, hence since your starting number is None , its always the smallest.

You can put a check that if small is None to initialize with the input ( this should set your small to the first inputted number).

Example -

small = None
larg = None
count = 0

while True:
    inp = raw_input("Enter a number: ")
    if inp == "done" : break

    try:
        num = float (inp)

    except:
        print "Invalid number"

    if small is None or num < small:
        small = num

print "Done"
print small

Naman Sogani · Answer 2 · 2015-07-10T06:03:44.457

0

You cannot initiate small as None value initially. Otherwise your statemtent

if num < small:

will evaluate to False everytime. Because you are comparing None value with a float value and None is smaller than every number. Do something like this

if small is None or num < small:
    small = num

edited Jul 10 '15 at 06:03

answered Jul 10 '15 at 05:58

Naman Sogani

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What if the user enters all numbers greater than 9999999? – Anand S Kumar Jul 10 '15 at 06:03
yea thanks that give some advantage of making code smaller :D – Solo Jul 10 '15 at 06:07

score 0 · Answer 3 · answered Jul 10 '15 at 06:09

I can suggest something like this

input_list = []

while True:
    inp = raw_input("Enter a number: ")
    if inp == "done" : break

    try:
        input_list.append(float(inp))
    except:
        print "Invalid number"
        continue

    smalest = min(input_list[-2:])
    print smalest

    input_list.append(input_list.pop(input_list.index(smalest)))

print "Done"

score 0 · Answer 4 · answered Jul 10 '15 at 06:47

This is a fairly simple way of doing it. I haven't tried breaking it by typing gibberish into the prompt but I think it works ok.

numbers = []

def asking():
    while True:
        number = raw_input("Enter a number:")
        if number == "stop":
            break
        try:
            number = float(number)
            numbers.append(number)
        except:
            print "Try again."
            continue

    return min(numbers)

print asking()

Finding minimum of the input numbers

4 Answers4