Understanding Condition Logic

I'm writing a python program that takes a given sentence in plan English and extracts some commands from it. It's very simple right now, but I was getting some unexpected results f

Solution 1:

Use any here:

screens = ("workspace" , "screen" , "desktop" , "switch")
threes = ("3" , "three", "third")

if any(x in command for x in screens) and any(x in command for x in threes):
    os.system("xdotool key ctrl+alt+3")
    result = True

Boolean or:

x or y is equal to : if x is false, then y, else x

In simple words: in a chain of or conditions the first True value is selected, if all were False then the last one is selected.

>>> False or []                     #all falsy values
[]
>>> False or [] or {}               #all falsy values
{}
>>> False or [] or {} or 1          # all falsy values except 1
1
>>> "" or 0 or [] or "foo" or "bar" # "foo" and "bar"  are True values
'foo

As an non-empty string is True in python, so your conditions are equivalent to:

("workspace") in command and ("3" in command)

help on any:

>>> print any.__doc__
any(iterable) -> bool

Return True if bool(x) is True for any x in the iterable.
If the iterable is empty, return False.
>>> 

Solution 2:

"workspace" or "screen" or "desktop" or "switch" is an expression, which always evaluate to "workspace".

Python's object has truth value. 0, False, [] and '' are false, for example. the result of an or expression is the first expression that evaluates to true. "workspace" is "true" in this sense: it is not the empty string.

you probably meant:

"workspace" in command or "screen" in command or "desktop" in command or "switch" in command

which is a verbose way to say what @Ashwini Chaudhary has used any for.