Hey guys, in this blog we will see a Python Program to Slice Lists.
The format for list slicing is [start:stop:step].
- start is the index of the list where slicing starts.
- stop is the index of the list where the slicing ends.
- step allows you to select the nth item within the range start to stop.
Get all the Items
# Python Program to Slice Lists my_list = [1, 2, 3, 4, 5] print(my_list[:])
Output
[1, 2, 3, 4, 5]
When we want to access all the items of the list we use [:] which means all.
Get all the Items After a Specific Position
# Python Program to Slice Lists my_list = [1, 2, 3, 4, 5] print(my_list[2:])
Output
[3, 4, 5]
- When we want to access all the items of the list after a specific position we use [2:] which means all the elements starting from position 2 to end.
- Indexing will be 0 indexed which means position 2 in 0 indexed will actually be position 3 if we start counting from 1.
- Notice position 2 is inclusive.
Get all the Items Before a Specific Position
# Python Program to Slice Lists my_list = [1, 2, 3, 4, 5] print(my_list[:2])
Output
[1, 2]
- When we want to access all the items on the list before a specific position we use [:2] which means all the elements start from starting to this position.
- Notice position 2 is exclusive.
Get all the Items from One Position to Another Position
# Python Program to Slice Lists my_list = [1, 2, 3, 4, 5] print(my_list[2:4])
Output
[3, 4]
- When we want to access all the list items in a specific range we use [2:4] which means all the elements starting from position 2 to 4.
- Notice that 2 is inclusive and 4 is exclusive.
Get the Items at Specified Intervals
# Python Program to Slice Lists my_list = [1, 2, 3, 4, 5] print(my_list[::2])
Output
[1, 3, 5]
- When we want to change the step size while accessing items of a list we use [::2] which means all the elements from start to end but the step size is 2.
- After 1 it should ideally print 2 but as our step size is 2 it will print 3.
Start indexing from the last item
If you want the indexing to start from the last item, you can use the negative sign -.
# Python Program to Slice Lists my_list = [1, 2, 3, 4, 5] print(my_list[::-2])
Output
[5, 3, 1]
- Similar to above but here step size is -2 which means starting from the end and taking 2 steps back every time.
Slicing items from one position to another
If you want the items from one position to another, you can mention them from start to stop.
# Python Program to Slice Lists my_list = [1, 2, 3, 4, 5] print(my_list[1:4:2])
Output
[2, 4]
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