Question

I have this code:

def GetSteamAccts(): #Get list of steam logins on this computer.
    templist = []
    Steamapp_Folders = ["C:\\Program Files (x86)\\Steam\\steamapps\\", "C:\\Program Files\\Steam\\steamapps\\"] #Check both of these directories.
    for SF_i in range(len(Steamapp_Folders)):
        if os.path.exists(Steamapp_Folders[SF_i]): #If the directory even exists...
            Steam_AppDir_Items = os.listdir(Steamapp_Folders[SF_i]) #List items under steam install directory.
            for S_AD_i in range(len(Steam_AppDir_Items)): #Make sure the user doesn't have any files in here...
                if os.path.isdir(Steamapp_Folders + Steam_AppDir_Items[S_AD_i]): #If our path is a directory...
                    templist.append(Steam_AppDir_Items[S_AD_i])  #Add it to our list of logins.
                                                                 #(If some idiot puts extra folders in here,
                                                                 #it's their own damn fault when it shows on the list.)
    return templist #Return a (not so) properly filtered list of steam logins.

My problem is, it looks AWFULLY ugly to me. I made a list of 2 paths (only 1 will ever exist), loop over those paths, then I have to get a list of the items in those paths, and then traverse those and filter out non-directories from that in order to get a pseudo-list of steam logins on a users computer. (Basically just getting a list of any existing directories (directories only!) under either of those 2 paths)

Is there a shorter way of doing this (Other than condensing for loops into single lines?)?

I would much rather be given an english-worded solution so I can put it together myself; rather than code. It’s the only way I’ll truly learn the proper way. Even a nice little hint or excerpt so I can figure it out on my own would be nice.

And: Do lists in for loops always have to be traversed like:

for x in range(len(somelist)):

or is there something shorter than using range(len( ?

Answer 1

for i in range(len(somelist)):
   something( somelist[i] )

should be written as

for x in somelist: 
    something( x )

Also you can write everything much shorter:

def GetSteamAccts():
    Steamapp_Folders = [f for f in ("C:\\Program Files (x86)\\Steam\\steamapps\\", 
                                    "C:\\Program Files\\Steam\\steamapps\\") 
                          if os.path.isdir(f)]
    return [os.path.join(root, folder) 
                    for root in Steamapp_Folders 
                    for folder in os.listdir(root) 
                    if os.path.isdir( os.path.join(root, folder)) ]

This looks cleaner and actually does what you wanted: 😉

def subfoldernames( root ):
    for folder in os.listdir(root):
        path = os.path.join(root, folder)
        if os.path.isdir(path):
            yield folder # just the name, not the path

# same, just shorter:
def subfoldernames( root ):
    # this returns a generator, written as a generator expression
    return ( folder for folder in os.listdir( root ) 
                    if os.path.isdir(os.path.join( root, folder )) )

def GetSteamAccts():
        Steamapp_Folders = ("C:\\Program Files (x86)\\Steam\\steamapps\\", 
                                             "C:\\Program Files\\Steam\\steamapps\\")
        for folder in Steamapp_Folders:
            if os.path.isdir(folder):
                # only the subfolders of the first path that exists are returned
                return list(subfoldernames( folder ))