Built-in data structures in Python

Python has some simple built-in types, such as int, float, complex, str, bool. It also has some complex built-in types, such as List, Dict, Tuple, Set.

Lists-Lists are one of the data types in Python. Lists are collections of objects, which are ordered and mutable. In Python, it is written in square brackets [].

How to build a list

my_list=["car","bus","truck"]
print(my_list)

How to access ListItems

We can access list items by referencing the index number:

Return position1the item at this position.

my_list=["car","bus","truck"]
print(my_list[1)]

How to change list values

Using index numbers, we can change the value of the item.

my_list=["car","bus","truck"]
my_list[2] = "van"
# The values are mutable
print(my_list)

How to apply loops in the list

We can use a for loop to traverse the items in the List.

my_list=["car","bus","truck"]
for x in my_list:
　　　print(x)

Some methods in the list

List methods

Python has some built-in methods that we can use in lists.

Dictionaries-Dictionaries are unordered collections of elements, using keys instead of positions. Dictionaries are an abstract data type in Python. Dictionaries have two parameters, one is the key, and the other is the value. Each key is associated with a value, so we can say that dictionaries are associative arrays.

Example

>>> student = {"Aadrika":001, "Adwaita":009, "Sakya":011, "Sanj":022}

Here, we use student records, and what we want to do is use the student name as the index.

>>> student = {"Aadrika":001, "Adwaita":009, "Sakya":011, "Sanj":022}
>>> student["Adwaita"]
009

In these examples, our dictionary is the student, and there is an order in the dictionary. Just like the first element is "Aadrika", the second element is "Adwaita", and so on. But there is no order in the dictionary. This is why the output of the student dictionary does not reflect the "original order".

If you want to add an element.

>>> student["Krishna"] =　111
>>> student
student = {"Aadrika":001, "Adwaita":009, "Sakya":011, "Sanj":022,"Krishna":111}

Therefore, the initial dictionary is empty, and then values are taken one by one in the incremental process.

Tuples-Tuples are a group of objects in Python. They are separated by commas (", "). In terms of indexing, tuples are similar to lists. Tuples are mainly immutable. They also have comparability and hashability, so we can easily sort them. In Python dictionaries, tuples are used as keys.

How to create a tuple

my_tuple={"car","bus","truck"}
print(my_tuple)

How to access tuple items

We can access tuple items by referencing the index number.

Return item to position1.

my_tuple={"car","bus","truck"}
print(my_tuple[1)]

How to change tuple values

If a tuple is created, then we will not be able to change its values. Tuples are immutable.

We cannot change the values in the tuple.

my_tuple={"car","bus","truck"}
my_tuple[3] = "van"
# The values are unchangeable
print(my_tuple)

How to apply loops to tuples

We can use a for loop to traverse the items in the tuple.

my_tuple={"car","bus","truck"}
for x in my_tuple:
　　　print(x)

Tuple methods

Python has two built-in methodscount()andindex(). We can use these methods in tuples.

set-In mathematics, a set is a collection of different objects. For example, here it is assumed that3a number, when considered separately, the number2,4and6They are different objects, but when considered together, they form a set of size3A single set, denoted as {2,4,6}

In Python, set is very useful because set is a highly optimized method, because it is easy to check whether there is any specific element in the set or not.

Different operations on sets

Set methods

1.add(x) method: If the element is not in the list, it will be added to the list.

A = {"AA", "BB", "CC"}
A.add("DD")　
-> add DD in A set.

2.union(s) method: This method returns the union of two sets. For union operations, please use the “ |” operator.

A = {"AA", "BB", "CC"}
B = {"MM", "NN"}
Z = A.union(B)
OR
Z = A|B
-> Set Z will have elements of both A and B

3.intersection method: This method returns the intersection of two sets. In this case, the “＆” operator can also be used.

S = A.intersection(B)
-> Set S will contain the common elements of A and B

4.difference method: This method returns a set of elements that belong to the first group but not to the second group. We can use the “-”operator.

S = A.difference(B)
OR
S = A – B
-> Set S will have all the elements that are in A but not in B

5.clear()Method: Clear the entire set.

B.clear()
-> Clears B set

Set operators

The set and frozen set support the following operators