slice(start:stop[:step])
is an object usually containing a portion of a sequence. A slice is created using the subscript notation, with colons between numbers when several are given, such as in variable_name[1:3:5].
Arguments
This function can be used to slice tuples, arrays and lists.
The value of the start
parameter (or None if not provided)
The value of the stop
parameter (or last index of sequence)
The value of the step
parameter (or None if not provided). It cannot be 0.
All three must be of integer type.
Return
If only stop
is provided, it generates portion of sequence from index 0
till stop
.
If only start
is provided, it generates portion of sequence after index start
till last element.
If both start
and stop
are provided, it generates portion of sequence after index start
till stop
.
If all three start
, stop
and step
are provided, it generates portion of sequence after index start
till stop
with increment of index step
.
Example
a = [1, 2, 3, 4, 5, 6, 7, 8]
print(a[:5]) # prints [1, 2, 3, 4, 5]
print(a[2:]) # prints [3, 4, 5, 6, 7, 8]
print(a[2:5]) # prints [3, 4, 5]
print(a[2:7:2]) # prints [3, 5, 7]
You can index the last index of a sequence by using -1
:
a = [1, 2, 3, 4, 5, 6]
print(a[-1]) # prints 6
print(a[2:-1]) # prints [3, 4, 5]
You can flip a sequence by using the [::-1]
slice notation:
a = [1, 2, 3, 4, 5, 6]
print(a[::-1]) # prints [6, 5, 4, 3, 2, 1]