The Assignment Sratement. There is a variation on the
assignment
statement called a
multiple-assignment
statement
that works nicely with tuple
s. We looked at
this in the section called “Multiple Assignment Statement”. Multiple variables are
set by decomposing the items in the
tuple
.
>>>
x,y=(1,2)
>>>
x
1
>>>
y
2
An essential ingredient here is that a
tuple
has a fixed and known number of elements.
For example a 2-dimensional geometric point might have a
tuple
with
x
and
y
. A 3-dimensional point might be a
tuple
with
x
,
y
, and
z
.
This works well because the right side of the assignment statement
is fully evaluated before the assignments are performed. This allows
things like swapping two variables with x,y=y,x
.
The
for
Statement. The
for
statement also works directly with
sequences like tuple
s. The
range
function that we have used creates a
list
(a kind of sequence covered in the next
section). A tuple
is also a sequence and can be
used in a
for
statement.
s= 0
for i in ( 1,3,5,7,9, 12,14,16,18, 19,21,23,25,27, 30,32,34,36 ):
s += i
print "total",s