How to use List in Python ?

A list is a collection which is ordered and changeable. In Python lists are written with square brackets.

Use the code below to create & print a list 

mycolors= [“red”, “blue”, “green”]
print(mycolors)

You access the list items by referring to the index number, index start from 0, in case you want to access/print the

last item from the list “mycolors” above you can use the code

print( mycolors[2] )

You can even use the Negative indexing means beginning from the end, -1 refers to the last item, -2 refers to the second last item etc. You can print last item in the list using the code print( mycolors[-1] )

You can also specify a range of indexes by specifying where to start and where to end the range.

thislist = [“apple”, “banana”, “cherry”, “orange”, “kiwi”, “melon”, “mango”]
print(thislist[2:5])

The code above will Return the third, fourth, and fifth item

Note: The search will start at index 2 (included) and end at index 5 (not included).

We can use the code below to change the value of any item in the list :

Check list length

mycolors= [“red”, “blue”, “green”]
print(len(mycolors))

Check if Item Exists

To determine if a specified item is present in a list use the in keyword:

mycolors= [“red”, “blue”, “green”]
if “blue” in mycolors:
  print(“Yes, ‘blue’ is in the mycolors list”)

Add Items

To add an item to the end of the list, use the append() method:

mycolors= [“red”, “blue”, “green”]
mycolors.append(“orange”)
print(mycolors)

To add an item at the specified index, use the insert() method

Insert an item as the second position:

mycolors= [“red”, “blue”, “green”]
mycolors.insert(1,“orange”)
print(mycolors)

Remove Item

There are several methods to remove items from a list

The remove() method removes the specified item:

The pop() method removes the specified index, (or the last item if index is not specified):

The clear() method empties the list:

Make a copy of a list with the copy() method:

mycolors= [“red”, “blue”, “green”]
mylist = mycolors.copy()
print(mylist)

Make a copy of a list with the list() method:

mycolors= [“red”, “blue”, “green”]
mylist = list(mycolors)
print(mylist)

How to Print all items in the list using loop :

mycolors= [“red”, “blue”, “green”]
for x in mycolors:
  print(x)

List Methods

Python has a set of built-in methods that you can use on lists.

You can find more Python Tutorials  on https://www.w3schools.com/python