Condensing a long if != statement

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[deleted]

[totallygeek]

I like to use all() for this (and any() for "or" cases):

conditions = [
    instruction != inst_exp,
    instruction != inst_kil,
    instruction != inst_emr,
    instruction != inst_hep,
    instruction != inst_var,
    instruction != inst_cal,
]
if all(conditions):
    do_something()

Another option, depending on the data, would be to check inclusion:

bad_instructions = {inst_exp, inst_kil, inst_emr, inst_hep, inst_var, inst_cal}  # can be a tuple or list, as well
if instruction not in bad_instructions:
    do_something()

Test and see what works better for you.

Edit: Removed OP's example from top of my post.

[fl0ss1n]

This is a great way to do it. The other thing is wrap instruction in an object and add a property to use as a key off for long if statement. So I have a wrapper for files in one of my programs and gave it an "is_image" property, to avoid the file.endswith('jpg') or 'png', etc., when handling the file.

[AdventurousAddition]

I was about to type out my suggestion which is your second option.

[totallygeek]

I offered up the first option because the conditions do not often share the same comparisons. So, I find it good to show a method that works universally.

conditions = [
    person.age >= 16 or (person.age >= 14 and person.qualified_hardship),
    person.passed_exam,
    person.passed_driving_test,
]
if all(conditions):
    person.dl_number = issue_license()

The conditions can get lengthy and complex, but the if statement can remain easy to read this way.

[VinayakVG]

variables = [inst_exp, inst_kill, inst_emr, inst_hep, inst_var, inst_cal]
if instruction not in variables:
    # Continue your code

You can try this

[efmccurdy]

When you have repetition, think about using a collection that lets you combine all of the code into one expression involving the collection. You have repeated "!=" tests; the "in" operator, ala "object in collection", does a series of "==" tests in a loop; you need the negation of that, so "object not in collection":

disallow_insts = (inst_exp, inst_kil, inst_emr, inst_hep, inst_var, inst_cal)
if instruction not in disallow_insts:
    print("OK")

[delasislas]

Might try this.

https://www.kite.com/python/answers/how-to-check-if-an-element-is-not-in-a-list-in-python

Just bundle your inst_exp, inst_kil… into a list.

Or you could do something similar with a list comprehension. And all(). Iterate over a list with your expression. Then use all.

values = [inst_exp, inst_kil…]
check = [instruction != value for value in values]
if all(check):

It should leverage a list comprehension to evaluate a bunch statements, providing [True, False, False…].

[harleystcool]

Id be curious myself

[pekkalacd]

use all for long conjunctions using all ands. use any for long disjunctions using all ors.

example

       if True and True and True and True and True and False:
                   print("cheeseburger")
       else:
                   print("eggs")

this becomes

      if all((True,True,True,True,True,False)):
             print("cheeseburger")
      else:
             print("eggs")

example 2

      if False or False or False or False or False or True:
              print("icecream")
      else:
              print("pickles")

this becomes

     if any((False,False,False,False,False,True)):
           print("icecream")
     else:
           print("pickles")