control of user input
<p>I'm wondering why my input control here doesn't work. I tried it with only <code>userOption != "1"</code> and it worked fine (Side note: Ignore the other functions.)</p>

<pre><code>userOption = str(input("Chose option 1, 2 or \"E/e to exit\": "))
print(userOption)
while(userOption != "1" or userOption != "2" or userOption != "e"
        or userOption != "E"):
    reply = (userOption + " is not a valid option")
    print(reply)
    userOption = input("Chose option 1, 2 or \"E/e to exit\": ")
    if userOption == "1":
        validEntry("Celsius")
        C_to_F(int(userInput))
        print(F)
    elif userOption == "2":
        validEntry("Fahrenheit")
        F_to_C(int(userInput))
        print(C)
    else:
        input("Thank you. Press enter to close this screen in the exe mode.")
</code></pre>

<pre><code>while(userOption != "1" or userOption != "2" or userOption != "e"
    or userOption != "E"):
</code></pre>

<p>That logic will produce a true result <em>no matter what the user types</em>.  As others have said, you need to use <code>and</code> here instead of <code>or</code>.</p>

python