I'm trying to use slicing in Python to print the first two values from a list. However, I only get one value in the output, and I can't figure out why. Here's my code:
a_list = [1,2,3]
b_list = a_list[1:2]
print(b_list)
I expected the output to be the first two values, but instead, I get:
Output is: [2]
Why is the output only [2]? Can anyone help me understand how slicing works in this case?
What is : in Python? It is an operator for slicing a list and it is an alias for slice(start, end, step) function.
How can I use it and how it works? When you use it with a list such as [1,2,3] like [1,2,3][0:2] you get all elements from 0th to first. In fact, 2 is excluded.
And please mind that array indices start from 0, so 1 is the 0th element of the list:
[1,2,3][0] == 1 # True
And if you want to get all elements you can use [1,2,3][0:3].
Two more points:
step like [start:end:step] and you can specify step size, for example [1,2,3,4][0:4:2] will give you [1,3][:4] means [0:4], [0:] means [0:last_index+1], and [:] means [0:last_index+1]