What is an alternative to execfile in Python 3?


It seems they canceled in Python 3 all the easy way to quickly load a script by removing execfile()

Is there an obvious alternative I"m missing?

Answer rating: 449

According to the documentation, instead of





Answer rating: 229

You are just supposed to read the file and exec the code yourself. 2to3 current replaces

execfile("somefile.py", global_vars, local_vars)


with open("somefile.py") as f:
    code = compile(f.read(), "somefile.py", "exec")
    exec(code, global_vars, local_vars)

(The compile call isn"t strictly needed, but it associates the filename with the code object making debugging a little easier.)


Answer rating: 79

While exec(open("filename").read()) is often given as an alternative to execfile("filename"), it misses important details that execfile supported.

The following function for Python3.x is as close as I could get to having the same behavior as executing a file directly. That matches running python /path/to/somefile.py.

def execfile(filepath, globals=None, locals=None):
    if globals is None:
        globals = {}
        "__file__": filepath,
        "__name__": "__main__",
    with open(filepath, "rb") as file:
        exec(compile(file.read(), filepath, "exec"), globals, locals)

# execute the file


  • Uses binary reading to avoid encoding issues
  • Guaranteed to close the file (Python3.x warns about this)
  • Defines __main__, some scripts depend on this to check if they are loading as a module or not for eg. if __name__ == "__main__"
  • Setting __file__ is nicer for exception messages and some scripts use __file__ to get the paths of other files relative to them.
  • Takes optional globals & locals arguments, modifying them in-place as execfile does - so you can access any variables defined by reading back the variables after running.

  • Unlike Python2"s execfile this does not modify the current namespace by default. For that you have to explicitly pass in globals() & locals().

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