"Stephen Nelson-Smith" <sanel...@gmail.com> wrote
To upack your variables a and b you need an iterable object on the right
side, which returns you exactly 2 variables
What does 'unpack' mean? I've seen a few Python errors about packing
and unpacking. What does it mean?
It has a coup[le of uses, the one being referred to here is where we
take a sequence of values and assign each value to a corresponding
variable on the other side of the assignment.
x,y = (val1, val2)
which is equivalent to
x = val1; y = val2
or
j,k = [3,4]
j=3; k=4
You can also pack a set of variables into a single value:
t = 3,4,5
or
s = 4,5,6
But this is really just tuple assignment without the parentheses! :-)
Pack/Unpack can also refer to an operation of the struct module,
which does a similar thing with binary data.
So if we have a set of bytes b we can extract the bytes into a
set of variables using a format string and the struct.unpack()
operation. Conversely you use struct.pack to encode a sequence
of values into a sequence of bytes.
But thats a more specialised usage, not seen so often.
HTH
--
Alan Gauld
Author of the Learn to Program web site
http://www.alan-g.me.uk/
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