python - How is returning the output of a function different than printing it? -

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in previous question, andrew jaffe writes:

in addition of other hints , tips, think you're missing crucial: functions need return something. when create autoparts() or splittext(), idea function can call, , can (and should) give back. once figure out output want function have, need put in return statement.

def autoparts():     parts_dict = {}     list_of_parts = open('list_of_parts.txt', 'r')      line in list_of_parts:         k, v = line.split()         parts_dict[k] = v      print(parts_dict)  >>> autoparts() {'part a': 1, 'part b': 2, ...}

this function creates dictionary, not return something. however, since added print, output of function shown when run function. difference between returning , printing it?

print prints out structure output device (normally console). nothing more. return function, do:

def autoparts():   parts_dict={}   list_of_parts = open('list_of_parts.txt', 'r')   line in list_of_parts:         k, v = line.split()         parts_dict[k] = v   return parts_dict

why return? if don't, dictionary dies (gets garbage collected) , no longer accessible function call ends. if return value, can other stuff it. such as:

my_auto_parts=autoparts()  print my_auto_parts['engine']

see happened? autoparts() called , returned parts_dict , stored my_auto_parts variable. can use variable access dictionary object , continues live though function call over. printed out object in dictionary key 'engine'.

for tutorial, check out dive python. it's free , easy follow.


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