Python list operations

map(function, sequence)

calls function(item) for each of the sequence's items and returns a list of the return values.

filter(function, sequence)

returns a sequence consisting of those items from the sequence for which function(item) is true.

reduce(function, sequence)

returns a single value constructed by calling the binary function function on the first two items of the sequence, then on the result and the next item, and so on.

list.append(x)

Add an item to the end of the list; equivalent to a[len(a):] = [x].

list.extend(L)

Extend the list by appending all the items in the given list; equivalent to a[len(a):] = L.

list.insert(i, x)

Insert an item at a given position. The first argument is the index of the element before which to insert, so a.insert(0, x) inserts at the front of the list, and a.insert(len(a), x) is equivalent to a.append(x).

'combinator'.join(list)

Joins all list items into a combinator-separated string.

'combinator'.join(list[indices])

Joins list items at 0-based specified indices into a combinator-separated string.

len(list)

Measures a list's length in words.

list.remove(x)

Remove the first item from the list whose value is x. It is an error if there is no such item.

list.pop([i])

Remove the item at the given position in the list, and return it. If no index is specified, a.pop() removes and returns the last item in the list.

list.index(x)

Return the index in the list of the first item whose value is x. It is an error if there is no such item.

list.count(x)

Return the number of times x appears in the list.

list[index]

Returns the list item at 0-based specified index. [-1] returns the last item.

list.reverse()

Reverse the elements of the list, in place.

list.sort(cmp=None, key=None, reverse=False)

Sort the items of the list in place (the arguments can be used for sort customization, see sorted() for their explanation).

sum(sequence)

summing numbers