Python globally import in a for loop (preferrably Python 3.x)

Question

My code is this:

for module in ["ffmpy","os","sys"]:
    try:
        __import__(module)
    except:
        print("Can't import ["+module+"]")

So, I want to import this globally, but it doesn't seem to do this. After this code, I have sys.path.insert(0, r"C:\Users\david\Desktop\scripts"),and the python console tells me: NameError: name 'sys' is not defined. I don't know what I'm doing wrong, but you hopefully do.

edit: This Question is not a duplicate, because i don't 'just' want to import from string, but do that from a for loop. I basically want to import from a string, in a loop, globally.

I can see why you might want to conditionally handle importing of `ffmpy`, but `os` and `sys`…?! If those don't exist… then what?! — deceze, Nov 20 '18 at 11:48
@deceze I think the question is interesting even without the `try-except` block. — Ma0, Nov 20 '18 at 11:50
@deceze Well I did that because of lazy programming, but I get your point. I just wrote everything to import in that line. — Riedler, Nov 20 '18 at 11:51
Possible duplicate of [import module from string variable](https://stackoverflow.com/questions/8718885/import-module-from-string-variable) — Tobias Brösamle, Nov 20 '18 at 11:53
Well, don't be lazy. It's *good* that `import` raises exceptions if things can't be imported, and you would need a really good reason to want to suppress those. — deceze, Nov 20 '18 at 11:54
The module has been imported but not bound to the name `sys` in your scope. — Stop harming Monica, Nov 20 '18 at 11:55

Andrew McDowell · Accepted Answer · 2018-11-20T12:15:19.907

I think the issue is that although you have imported the library sys you haven't defined the object sys.

Consider the two following examples:

# Doesn't work
__import__('sys')
sys.callstats()

This throws the same error: "name 'sys' is not defined", while

# Works
sys = __import__('sys')
sys.callstats()

works fine.

You need to store the imported objects somewhere. A dictionary seems sensible:

import_dict = dict()

for module in ["ffmpy","os","sys"]:
    try:
        import_dict[module] = __import__(module)
    except:
        print("Can't import ["+module+"]")


import_dict['sys'].path.insert(0, r"C:\Users\david\Desktop\scripts")

Should work.

Edit:

As suggested by @9769953 in the comments, an even better solution is to use:

globals()[module] = __import__(module)

which then allows you to access sys directly as you would normally.

Or if you really want, use `globals()[module] = __import__(module)` and then use `sys` and others directly, as in `sys.path.insert(0, r"C:\Users\david\Desktop\scripts")`. — 9769953, Nov 20 '18 at 12:10

Python globally import in a for loop (preferrably Python 3.x)

1 Answers1