Python condensed if statements-CodePudding

I am experimenting with how to condense if statements within my code. I have a project I am working on that has several "if" statements (too many to keep track of) and want to figure out a way to condense them. Obviously this involves a for loop, but I am having trouble adding additional operations within this loop.

I came up with the following working example to demonstrate my issue:

num=6

if_options = [num==5, num==6]

for i in range(len(if_options)):
    if if_options[i]:
        print(num)

I want to add an additional piece to the code. This additional piece will execute an operation within the if statement. See following non-working example as a framework for what I am trying to accomplish:

num=6

if_options = [num==5, num==6]
operations = [num=num 1, num=num-1]

for i in range(len(if_options)):
    if if_options[i]:
        operations[i]
        print(num)

For whatever reason, it will not execute the operation portion of the code and fails with a syntax error. It does not let me declare the command "num=num 1" (without quotes) within a list, however this declaration is necessary for executing the command. I feel like I am missing one little thing and it should be an easy fix. Thank you in advance!!

CodePudding user response：

The problem here is that the operations are evaluated when you create the list of them. You want to write them as strings, and then eval/exec them in the loop. I will assume you also want the conditions evaluated in the loop.

num = 6

if_options = ['num==5', 'num==6']
operations = ['num=num 1', 'num=num-1']

for i in range(len(if_options)):
    if eval(if_options[i]):
        exec(operations[i])
        print(num)

CodePudding user response：

why not functions?

def check(inp):
    #you can do some logic and type checking here
    return type(inp)==int # for example, or return arguments to pass to the operatiins

def operation(inp2):
    if inp2: # check if true or not empty, as an example
        #do some operations

# and then you do something like

for x in input_of_things:
    operation( check( x ) )

CodePudding user response：

You could use lambda expressions too.

num = 6
if_option_checks = [lambda x: x == 5, lambda x: x == 6]
operations = [lambda x: x   1, lambda x: x - 1]
for check, operation in zip(if_option_checks, operations):
    if check(num):
        num = operation(num)

Or you could use dictionaries and lambda expressions

num = 6
if_option_checks = {"add": lambda x: x == 5, "sub": lambda x: x == 6}
operations = {"add": lambda x: x   1, "sub": lambda x: x - 1}
for key, check in if_option_checks.items():
    if check(num):
        num = operations[key](num)