how to use “not” and “in” in conditional statements in python

Question

availableNums=["one","two","three","four","five"]
selectedNumbers=[]
for value in range(0,3):
    selectedNumbers.append(raw_input("Choose a number:"))

if selectedNumbers not in availableNums:
      print("The number "+str(selectedNumbers)+" isn't available/nBut it will be changed to six")

When I run this code and it asks for the numbers, I type in the numbers that are available in the list, but it still says that "The number ['one','two','three'] isn't available But it will be changed to six". Why is it doing that?

I think that I have to change the not or in part but I am not sure.

Answer 1

in checks membership: a in b is true if and only if a is a member contained by b .

Since availableNums is a tuple of ints, selectedNumbers , which is a list, isn't a member. You seem to be wanting to check whether selectedNumbers is a subset of availableNums .

You can either check each item in a loop:

for s in selectedNumbers:
    if s not in availableNums
        ....

Or you can convert them to sets, if you're okay with checking all at once and failing completely if any of the selected numbers are invalid:

if not set(selectedNumbers) < set(availableNums):
    ....

Note that < here, applied to sets, is the subset operator.

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Also, as noted in a comment, raw_input returns a string, but you're attempting to treat it as an integer. You can use int() to parse the input string.

Answer 2

selectedNumbers is a list. You are checking if the whole list is in availableNums , not if each number in selectedNumbers is in availableNums .

It sounds like you want something like:

for selectedNumber in selectedNumbers:
    if selectedNumber not in availableNums:
        # selectedNumber from selectedNumbers is not in availableNums

Edit: As hatshepsut pointed out, your code places strings in selectedNumbers , not integers. Use input instead of raw_input ¹ or convert to int .

¹ For Python 2. For Python 3, see What's the difference between raw_input() and input() in python3.x?