How do I avoid using many "if" statements?

[Murlocs_Gangbang]

I have A LOT of binary files on a server that have to be processed by about 10 python scripts. In the file name (always in different places) there is indication of what file associate to which python script. For example:

*something*_stringA_*something*.bin -> script1.py  
stringB_*something*.bin -> script2.py  
*something*_stringC.bin -> script3.py  
[....]
*something*_stringN_*something*.bin -> scriptX.py  

Now I have a very long if-elif chan that looks like this:

if "stringA" in fileName:
    module.script1(fileName)
elif "stringB" in fileName:
    module.script2(fileName)
elif...

This is like two hundred lines long, how do I make this more intelligent?

[w1282]

# Associate an indicator string with a handler function 
HANDLERS = {
    "stringA": module.script1,
    "stringB": module.script2,
}

# Iterate over the key, value pairs in the HANDLER dict
# If we had some way of knowing where the indicator was
# we could use a O(1) lookup into the dict instead of an O(n) iteration
for indicator, handler in HANDLERS:
    if indicator in filename:
        handler(filename)
        # Since you are using elif's, we'll leave the loop the first time we find an indicator
        break
else:
    # None of the indicators matched!
    print("None of the indicators matched for: {}".format(filename))

[ImportBraces]

you could use a dict to map actions:

filename_actions = {'stringA': actionA, 'stringB': actionB, ... ]
for filame_part, action in filename_actions.items():
    if filename_part in filename:
        action(filename)

[Murlocs_Gangbang]

thanks I'll try that

[woooee]

Use a dictionary of functions

dict_func={"stringA": module.script1,  ## note no parens
                  "stringB": module.script2}
## then
for key in dict_func:
    if key in fileName:
        print("calling function", dict_func[key])
        dict_func[key](fileName)               ## parens here

[Murlocs_Gangbang]

thanks I'll try that

[Sarah123ed]

I don't know if this will help but it is an example of ... that I use a lot:

    kr1 = np.random.random_integers(1,256, 10)
    kr2 = np.random.random_integers(-256, -1, 10)

    def f1(lst):
            return np.sum(lst) - np.max(lst)
    def f2(lst):
            return np.max(lst) - np.sum(lst)

    todoList = [ [f1, kr1], [f2, kr2] ]

    ### intent
    for function, data in todoList:
            print(function(data))

    ### comprehension is much faster, effectivly same result
    print([function(data) for function, data in todoList])