Lists
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Lists in Python are ordered sets of elements that use zero-based indexing. A list defined with five elements will have the first element at index 0 and the last element at index 4. Lists can be sliced to extract subsets, with optional start and end indices. If the start index is omitted, it defaults to 0, and if the end index is omitted for a list of length n it defaults to n. Lists support methods like append to add a single element to the end, extend to concatenate two lists, and insert to add an element at a specific index.
![[ lists ]](https://image.slidesharecdn.com/lists-100227014611-phpapp01/85/Lists-1-320.jpg)
![* First, you define a list of five elements. Note that they retain their original order. This is not an accident. A listis an ordered set of elements enclosed in square brackets.** A list can be used like a zero−based array. The first element of any non−empty list is always names [0].*** The last element of this five−element list is names [4], because lists are always zero−based.](https://image.slidesharecdn.com/lists-100227014611-phpapp01/85/Lists-3-320.jpg)
![Slicing Shorthand* If the left slice index is 0, you can leave it out, and 0 is implied. So colours[:3] is the same as colours[0:3]** Similarly, if the right slice index is the length of the list, you can leave it out. So colours[3:] is the same as colours[3:5], because this list has five elements.](https://image.slidesharecdn.com/lists-100227014611-phpapp01/85/Lists-5-320.jpg)
Lists
- 1. [ lists ]
- 3. * First, you define a list of five elements. Note that they retain their original order. This is not an accident. A listis an ordered set of elements enclosed in square brackets.** A list can be used like a zero−based array. The first element of any non−empty list is always names [0].*** The last element of this five−element list is names [4], because lists are always zero−based.
- 4. Negative List IndicesSlicing a List
- 5. Slicing Shorthand* If the left slice index is 0, you can leave it out, and 0 is implied. So colours[:3] is the same as colours[0:3]** Similarly, if the right slice index is the length of the list, you can leave it out. So colours[3:] is the same as colours[3:5], because this list has five elements.
- 6. Adding Elements to Lists.appendappend adds a single element to the end of the list..extendextend concatenates lists..insertinsert inserts a single element into a list.
- 7. example
- 8. The Difference between extend and append
- 10. Good Luke By \ salma subh