WEBVTT

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ok let's continue on what I might do is
delete these extra lines first that I added

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....and what
we're going to do now as I mentioned at

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the end of the previous video was going
to change the calls to center_text so that we

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can allow the output to go to a file so to do
that it's actually quite simple we need

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to put on line 14...and then if I just in

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dent this code here the various ones we actually
had and what we need to do is add

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an additional parameter and of course the paramter is gonna be the files so.....

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......

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.....

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so now we've done the output should
actually go to a file.....

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....so now we've done that we should fine that when we write this it will write it to

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the current folders so we should see the file called centered appear here in the

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project window so just run that

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you can see that is centered file came up their and if we double-click
that and have a look at it you can see there's our

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content correctly being sent to a file so that's obviously working nicely so

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that's one approach to creating a
function that allows text to be printed

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centered on the screen but like everything
else in programming there is always another way

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now if we've written this function back in Python 3.2 there was no flush parameter to print

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so we wouldn't have known to include a flush center_text now although the

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function would still work it would no
longer provide the same functionalities

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print from Python 3.3 and onward so what we can do
is we can take another approach instead

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and that's to write center_text so that it just returns a required string

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without making any attempt to actually
print it and that's also good opportunity

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to explain about returning values from
functions so what we're going to do here is

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changed the program first and then
described what the code is doing so we are gonna close this

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down we don't need that anymore we got our file open again our functions.py file and we are going to change the

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actual method this line here what we
need to do is instead of having a print here on

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line 12 what we want to do was do change
that to make that a.....

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....and we are going to get rid of this extra stuff at the end so we are only going to return the left margin plus

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the text so I'm going to delete the rest and now if we change it to where

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we had before here center_text we're
going to change this I'm going to comment out

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the width which are not using anymore

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put this back to indent so there is no indentation
we are gonna change the files or removed the file

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we are not gonna output it anymore......

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......

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....so as you can
see the function hasn't really changed

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much at all instead of passing a string
on to print we use a return key

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word to indicated that the string should be
returned when the function is called

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looking at line 18 the center_text function is called with a

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string spam and eggs and it returned a string to be centered with a width of 80 characters so

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the print function then prints out that
return value whatever value came back from the

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center_text function so it's
normal to struggle this at first when

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passing your own functions to other
functions but it's really no different

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things we've actually done such as
and I'll give an example we've done this

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before in the course we put.....

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.....

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....so you can see we have done
something similar there but again the

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concept is we got a function center_text and by typing this

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keyword it would return this statement what were doing is we are saying the
output that was going to be printed

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we are returning that to wherever this
was calles so in this case the center_text

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is how we called that particular
method and then whatever is returned is

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in sort of soaked up by the print method
automatically and then its printed out to the

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console I haven't actually run that's so we
should just run it to make sure that

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still works you can see that it still
does work and what I didn't do was

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actually delete these we should probably
delete those as well

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so we don't need those anymore we got our list of arguments args and because this routine is now literally only

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returning the text it would not be appropriate 
to have those extra parameters and there shouldn't

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be a comma here there should be a plus so if I do that

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and now if we run it we should find the right out put as you can see so one thing

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that can help and can be less confusing
if we assign the returned results to

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variables instead of printing them
directly

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so we are gonna make a change to the code
now just to show you an alternate way of

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doing this so instead of having the one line we could put......

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......

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.....

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....so lets run it first to confirm if it works for

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us

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same result as you can see but what we've
done is we've a assigned the value that has

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been returned from our function
center_text and we have assigned that to

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variable and we printed it out so you can
see the bottom line here is either by putting

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the name of the function in the call to
print direct which I did previously or

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by actually assigning the value that was
returned from a function into a variable

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and printing the variable out using print we got the
same result so basically its a different

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approach to centering text and you could see that that's working nicely so this

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was a different approach to
centering text because here we just created

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the string that should be printed but
we left it to the print function

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to do the actual printing the only named
parameters of print that we bothered about is sep

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anything else is not our concern so if
someone else wants to send the centered

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text to a file they could do so in a way that
they normally would so we could do

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something like this I'm just gonna get rid of these last 2 lines which we don't need

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and leave that in their so we got a reference in the source code and paste the code
again so we could do something like.....

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...so the actual calls to the

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function is going to be the same but when we go to
print it will add this......

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.....

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....so its still

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going to be outputted.....and for the next one we will do something similar.....

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.....

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.....so in

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the case of the s1 s2 and s5
variables

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we are calling the method and saving the
returned data that's come back from that

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method into a variable and outputting that
variables on the next line but also I've got 2

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examples one on line 34 and one on line 35 where we are recording the method direct without

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assigning the return value to a variable
temporarily before printing it out in other words

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we've use a mix of assigning the
return value to a variable and printing it out really just

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to show that the output can be sent to
a file in either way either formats is acceptable and if we just run

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that make sure it does work and you can see the file up here their so lets close down the run window and open menu and

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you can see we still got the data their so that's it
that's the basics of creating your own

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functions I'm gonna stop the video here
in the next video we will practice

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creating a few more functions and then
we'll actually have a challenge to

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hopefully help you understand the
concepts even better so see you in the next

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video