How do I execute (not import) a python script from a python prompt?

I need to execute a Py开发者_如何学JAVAthon script from an already started Python session, as if it were launched from the command line. I'm thinking of similar to doing source in bash or sh.

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In Python 2, the builtin function execfile does this.

execfile(filename)

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If you're running ipython (which I highly recommend for interactive python sessions), you can type:

%run filename 

or

%run filename.py

to execute the module (rather than importing it). You'll get file-name completion, which is great for ReallyLongModuleName.py (not that you'd name your modules like that or anything).