If I want to iterate over part of the list, the normal Python idiom is to
do something like this:
alist = range(50)
# first item is special
x = alist[0]
# iterate over the rest of the list
for item in alist[1:]
x = item
The important thing to notice is that alist[1:] makes a copy. What if
Steven D'Aprano wrote:
If I want to iterate over part of the list, the normal Python idiom is to
do something like this:
alist = range(50)
# first item is special
x = alist[0]
# iterate over the rest of the list
for item in alist[1:]
x = item
The important thing to notice is that
James Stroud wrote:
Steven D'Aprano wrote:
If I want to iterate over part of the list, the normal Python idiom is to
do something like this:
alist = range(50)
# first item is special
x = alist[0]
# iterate over the rest of the list
for item in alist[1:]
x = item
The important thing
Steven D'Aprano wrote:
[snip]
The important thing to notice is that alist[1:] makes a copy. What if the
list has millions of items and duplicating it is expensive? What do people
do in that case?
Are there better or more Pythonic alternatives to this obvious C-like
idiom?
for i in range(1,
Steven D'Aprano wrote:
Are there better or more Pythonic alternatives to this obvious C-like
idiom?
for i in range(1, len(alist)):
x = alist[i]
For small start values you can use itertools.islice(), e. g:
for x in islice(alist, 1, None):
# use x
You'd have to time at what point
Steven D'Aprano [EMAIL PROTECTED] wrote:
The important thing to notice is that alist[1:] makes a copy. What if
the list has millions of items and duplicating it is expensive? What
do people do in that case?
I think you are worrying prematurely.
On my system slicing one element off the front
Steven D'Aprano [EMAIL PROTECTED] writes:
for i in range(1, len(alist)):
x = alist[i]
a2 = iter(alist)
a2.next() # throw away first element
for x in a2:
...
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