The Assignment Statement. The variation on the
assignment
statement
called
multiple-assignment
statement also works
with list
s. We looked at this in the section called “Multiple Assignment Statement”. Multiple variables are set by
decomposing the items in the list
.
>>>
x,y=[1,"hi"]
>>>
x
1
>>>
y
"hi"
This will only work of the list
has a fixed
and known number of elements. This is more typical when working with
tuple
s, which are immutable, rather than
list
s, which can vary in length.
The
for
Statement. The
for
statement also works directly with
sequences like list
. The
range
function that we have used creates a
list
. We can also create
list
s other ways. We'll touch on various
list
construction techniques at several points
in the text.
s= 0
for i in [2,3,5,7,11,13,17,19]:
s += i
print "total",s
The
del
Statement. The
del
statement removes items from a
list
. For example
>>>
i = range(10)
>>>
del i[0],i[2],i[4],i[6]
>>>
i
[1, 2, 4, 5, 7, 8]
This example reveals how the
del
statement
works.
The i
variable starts as the
list
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ].
Remove i[0]
and the variable is [1, 2, 3, 4, 5, 6, 7,
8, 9].
Remove i[2]
(the value 3) from this new
list
, and get [1, 2, 4, 5, 6, 7, 8, 9].
Remove i[4]
(the value 6) from this new
list
and get [1, 2, 4, 5, 7, 8, 9].
Finally, remove i[6]
and get [1, 2, 4, 5, 7,
8].