Calling subroutines from a variable

Question

I'm trying to make a text game in python that's basically about exploring a fake hard drive through a CMD line. I'm experimenting with having the different subfolders saved in the code as different subroutines. Long story short I'm trying to make it so that you can call a subroutine from a variable name? Does anyone know if this is possible in python 3.6.3? Here's a test program to show my concept. Can anyone get this to work?

def level1():
    print("you have reached level 1")
def level2():
    print("you have reached level 2")
lvl = int(input("go to level: "))
lvl = str(lvl)
level = str("level"+lvl)
level()

Thanks for any help, -Rees :)

while you might be able to do this, you might want to think of other ways you can implement this. — Joe, Mar 02 '18 at 19:23

score 1 · Accepted Answer · answered Mar 02 '18 at 19:23

1

It can be done, but you don't want to do it that way. Instead, put your functions into a list or dict and call them from that.

levels = { 1 : level1,
           2 : level2 }
lvl = int(input("go to level: "))
levels[lvl]()

answered Mar 02 '18 at 19:23

glibdud

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score 0 · Answer 2 · answered Mar 02 '18 at 19:24

Two possibilities come to mind:

simple check with if ... elif.. else

def level1():
    print("you have reached level 1")
def level2():
    print("you have reached level 2")

while True:
    lvl = input("go to level: ").rstrip()
    if lvl == "1":
        level1()
    elif lvl == "2":
        level2()
    else: 
        print("Back to root")
        break

Second one is using eval() - this is dangerous. You can input arbritary python code and it will work (or crash) the program:

while True:
    lvl = input("go to level: ").rstrip()
    try:
        eval("level{0}()".format(lvl))
    except: # catch all - bad form
        print("No way out!")

Read: What does Python's eval() do?

Calling subroutines from a variable

2 Answers2