# 31.3. `modulefinder` — Find modules used by a script

Source code: Lib/modulefinder.py

This module provides a `ModuleFinder` class that can be used to determine the set of modules imported by a script. `modulefinder.py` can also be run as a script, giving the filename of a Python script as its argument, after which a report of the imported modules will be printed.

`modulefinder.``AddPackagePath`(pkg_name, path)

  Record that the package named pkg_name can be found in the specified path.

`modulefinder.``ReplacePackage`(oldname, newname)

  Allows specifying that the module named oldname is in fact the package named newname.

class `modulefinder.``ModuleFinder`(path=None, debug=0, excludes=[], replace_paths=[])

  This class provides `run_script()` and `report()` methods to determine the set of modules imported by a script. path can be a list of directories to search for modules; if not specified, `sys.path` is used. debug sets the debugging level; higher values make the class print debugging messages about what it’s doing. excludes is a list of module names to exclude from the analysis. replace_paths is a list of `(oldpath, newpath)` tuples that will be replaced in module paths.

  `report`()

    Print a report to standard output that lists the modules imported by the script and their paths, as well as modules that are missing or seem to be missing.

  `run_script`(pathname)

    Analyze the contents of the pathname file, which must contain Python code.

  `modules`

    A dictionary mapping module names to modules. See Example usage of ModuleFinder.

## 31.3.1. Example usage of `ModuleFinder`

The script that is going to get analyzed later on (bacon.py):

    import re, itertools

    try:
        import baconhameggs
    except ImportError:
        pass

    try:
        import guido.python.ham
    except ImportError:
        pass

The script that will output the report of bacon.py:

    from modulefinder import ModuleFinder

    finder = ModuleFinder()
    finder.run_script('bacon.py')

    print('Loaded modules:')
    for name, mod in finder.modules.items():
        print('%s: ' % name, end='')
        print(','.join(list(mod.globalnames.keys())[:3]))

    print('-'*50)
    print('Modules not imported:')
    print('\n'.join(finder.badmodules.keys()))

Sample output (may vary depending on the architecture):

    Loaded modules:
    _types:
    copyreg:  _inverted_registry,_slotnames,__all__
    sre_compile:  isstring,_sre,_optimize_unicode
    _sre:
    sre_constants:  REPEAT_ONE,makedict,AT_END_LINE
    sys:
    re:  __module__,finditer,_expand
    itertools:
    __main__:  re,itertools,baconhameggs
    sre_parse:  _PATTERNENDERS,SRE_FLAG_UNICODE
    array:
    types:  __module__,IntType,TypeType
    ---------------------------------------------------
    Modules not imported:
    guido.python.ham
    baconhameggs