Assalamualaikum warahmatullahi wabarakatuh. Hello everyone, on this occasion we will discuss about lists in python.
List is a data type in python for storing variable items. In the list we can store several types of variables at once. This list is sorted from index 0 and can be changed, added, deleted.

Make a List

How to make a list, by creating open and closed brackets and to separate one variable from another with a comma.

angka = [1,2,3,4]
list1 = ["satu", 2, True]

Reading List

We can read the list by accessing its index. For example, we have a list like this:

list1 = ["Dosen", "Mahasiswa", "Satpam", "Driver"]

to be able to print Students, we can access list1 with index 1.

print(list1[1])

If we want to print all the data in the list, we can use loops.

for l in list1:
   print(l)

Changing List

We can change the value in the list by:

list1 = ["Python", "PHP", "Ruby"]
list1[1] = "Golang"

In the code above, we change PHP to Golang

Add List

We can also add to the list we have with the append() and insert() functions, both of which have differences.
In the append() function, the data we enter will automatically be added to the last index.

list1 = ["Python", "PHP", "Ruby"]
list1.append("Golang")

The code above adds “Golang” to list1, where “Golang” will be added to the end. So that

list1 = ["Python", "PHP", "Ruby", "Golang"]

Whereas in the insert() function, we need 1 more parameter, where this parameter is a specific index that we want to put. For example

list1 = ["Python", "PHP", "Ruby"]
list1.insert(1, "Golang")

The code above, adds "Golang" to list1 with index to 1. So that list1 becomes

list1 = ["Python", "Golang", "PHP", "Ruby"]

Delete List

To delete a list, we can delete one or all data. We will discuss how to delete a single data first, to remove specific data, we can use the remove() function

list1 = ["Python", "PHP", "Ruby"]
list1.remove("Python")

The above code will delete list1 which has "Python" data, so list1

list1 = ["PHP", "Ruby"]

In addition to specific data, we can also delete specific indexes using the pop() function and the del keyword. the pop() function has an index parameter which we will remove.

list1 = ["Python", "PHP", "Ruby"]
list1.pop(1)

The above code removes list1 with index 1, so list1.

list1 = ["Python", "Ruby"]

If the pop() function does not have an index parameter, then the data to be deleted is the last data.

list1 = ["Python", "PHP", "Ruby"]
list1.pop()
list1 = ["Python", "PHP"]

As for the del keyword how to use it as follows:

list1 = ["Python", "PHP", "Ruby"]
del list1[0]
list1 = ["PHP", "Ruby"]

Deleting all data lists we can also use the del keyword and the clear() function. How to use the del keyword, namely:

list1 = ["Python", "PHP", "Ruby"]
del list1
list1 = []

while the use of the clear() function

list1 = ["Python", "PHP", "Ruby"]
list1.clear()
list1 = []

Sort List

If we have a list whose data is not sorted, we can sort it with the sort() function. This function can be used as a string or number data type. The sort function will automatically sort from small to large or ascending.

list2 = [1,9,4,28,17]
list2.sort()
list2 = [1,4,9,17,28]

If we want to sort from largest to smallest or descending, we can add the reverse = True parameter.

list2 = [1,9,4,28,17]
list2.sort(reverse = True)
list2 = [28,17,9,4,1]

Copy List

If we want to copy list then we can't use code

list2 = list1

Because list2 will reference list1, if list1 changes, list2 will automatically change as well. To overcome this, we can use the copy() and list() functions.

list1 = ["Python", "PHP", "Ruby"]
list2 = list1.copy()
list2 = ["Python", "PHP", "Ruby"]

Or we can add list()

list1 = ["Python", "PHP", "Ruby"]
list2 = list(list1)
list2 = ["Python", "PHP", "Ruby"]

Merge List

If we have 2 lists, then we want to combine them. Then the simplest way is to use the + operator.

list1 = ["Python", "PHP", "Ruby"]
list2 = ["Golang", "Vue", "React"]
list3 = list1 + list2
list3 = ["Python", "PHP", "Ruby", "Golang", "Vue", "React"]

Or we can also use the extend() function.

list1 = ["Python", "PHP", "Ruby"]
list2 = ["Golang", "Vue", "React"]
list1.extends(list2)
list1 = ["Python", "PHP", "Ruby", "Golang", "Vue", "React"]

That's enough for us to discuss the list, thank you :)