Cara menggunakan python implement indexing

In this lesson, you’ll see how to access individual elements and sequences of objects within your lists. Lists elements can be accessed using a numerical index in square brackets:

This is the same technique that is used to access individual characters in a string. List indexing is also zero-based:

>>>

List elements can also be accessed using a negative list index, which counts from the end of the list:

>>>

Slicing is indexing syntax that extracts a portion from a list. If a is a list, then a[m:n] returns the portion of a:

• Starting with postion m
• Up to but not including n
• Negative indexing can also be used

Here’s an example:

>>>

Omitting the first and/or last index:

• Omitting the first index a[:n] starts the slice at the beginning of the list.
• Omitting the last index a[m:] extends the slice from the first index m to the end of the list.
• Omitting both indexes a[:] returns a copy of the entire list, but unlike with a string, it’s a copy, not a reference to the same object.

Here’s an example:

>>>

A stride can be added to your slice notation. Using an additional : and a third index designates a stride (also called a step) in your slice notation. The stride can be either postive or negative:

>>>