Passing string from python programs to external programs

Hi all, On Linux, I do something like this $ program_to_execute < input_file ... get some output ... I have the content of the input_file as a string inside a python program and would like to pass this string to the external program from inside the python program and get back the programs output

Inverse of dict(zip(x,y))

Hi all, This might be trivial ... Can someone suggest a easy method to do the inverse of dict(zip(x,y)) to get two lists x and y? So, if x and y are two lists, it is easier to make a dictionary using d = dict(zip(x,y)), but if I have d of the form, d = {x1:y1, x2:y2, ...}, what is there any tric