python if-else only goes to else part

Question

I have the following simple python code, which checks the user input.

while True:
    num = raw_input("Enter the number :")
    if (num >= 1 and num <= 5):
        break
    else:
        print "Error! Enter again :"

When I give as input 0 or numbers greater than 5 it works correctly, but then I try to give an input from 1 to 5 and the program still goes to the else part. Could you help me to find my error?

Probably due to the fact that "num" is actually a string. You should convert it first. I would think that trying to compare a string with a number would be an error, but it's been awhile since I've written Python. — Carcigenicate, Apr 30 '16 at 16:22

Blender · Accepted Answer · 2016-04-30T16:33:01.787

3

num is a string, not a number. You need to convert the return value of raw_input into a number first with int():

>>> n = raw_input('Type stuff: ')
Type stuff: 123
>>> type(n)
<type 'str'>
>>> n
'123'
>>> int(n)
123
>>> type(int(n))
<type 'int'>

edited Apr 30 '16 at 16:33

answered Apr 30 '16 at 16:23

Blender

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Could you explain me the `In[2]-Out[2]`? Because if the user gives a `string` as input, I also want to reject it. – Marievi Apr 30 '16 at 16:29
@Marievi: `raw_input()` *always* returns strings. It's up to you to interpret what they mean. – Blender Apr 30 '16 at 16:31
Thanks for the clarification! – Marievi May 01 '16 at 15:09

score 2 · Answer 2 · answered Apr 30 '16 at 16:23

2

You need to cast it to int -

 num = int(raw_input("Enter the number :"))

As raw_input read line and converts it to string .

answered Apr 30 '16 at 16:23

ameyCU

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Just of of curiosity, why is this not an error? I can't think of a scenario where it makes sense to compare a string to a number. – Carcigenicate Apr 30 '16 at 16:24
1

@Carcigenicate You can find more details about this here: [How does Python compare string and int?](http://stackoverflow.com/questions/3270680/how-does-python-compare-string-and-int) – AKS Apr 30 '16 at 16:28
1

@Carcigenicate That generates an error in Python 3 and above versions. – ameyCU Apr 30 '16 at 16:29

python if-else only goes to else part

2 Answers2