Data Structures | learnpython.tech

Data structures are a technique of organizing data into a prespecified arrangement for efficient processing. Efficiency could be in favor of disk space or RAM, or execution performance.

Before any further explanation, lets us have a look at an example. Suppose you want to sort three numbers in ascending order stored in three different variables. Here is one way to do it.

a = 1
b = 0
c = 2

# Store sorted values
x = None
y = None
z = None

# First check for a
if a < b and a < c:
    x = a
    if b < c:
        y = b
        z = c
    else:
        y = c
        z = b

# Then Check for B
elif b < a and b < c:
    x = b
    if a < c:
        y = a
        z = c
    else:
        y = c
        z = a

# Then check for C
elif c < a and c < b:
    x = c
    if a < b:
        y = a
        z = c
    else:
        y = c
        z = a

print(x, y, z)

0 1 2

As you can observe, the solution is hard to follow, understand, and repetitive. It might give results for three variables, but what will happen when sorting thousands or millions of values. It's almost impossible to write programs using the above approach. Instead, we require a better way of managing data. Hence, we need Data Structures.

Data structures are a technique of organizing data into a prespecified arrangement for efficient processing.

Different Data Structures

These are some of the different data structures in computer science:

Stack
Queue
Array
Linked List
Binary Tree
Binary Search Tree
Heap
Hashing
Graph
Matrix

Covering data structures is beyond learning Python, as it is not a Python concept but a computer science concept.

You can read about data structures from external sources .

Data Structures supported in Python.

As we have learned, Data structures are imperative in structuring and processing data with maximum efficiency. Python provides several in-built data structures for processing data.

Python's in-built data structures:

We will explore data structures in Python in detail separately.

Here are five widespread usages of data structures.

Databases
File Systems
Mathematical Computing
Sorting Data
Categorizing Data
Instant Data Lookup, a.k.a, lookup tables

Data structures allow for optimal resource usage such as disk space or RAM, or computational performance.

# Using Lists to sort numbers

numbers = [1, 2, 0, 5, 4, 3, 9, 7, 8, 6]
no_of_elements = len(numbers)
for i in range(0, no_of_elements ):
    for j in range(0, no_of_elements ):
        if numbers [i] < numbers[j]:
            temp = numbers[i]
            numbers[i] = numbers[j]
            numbers[j] = temp
print(numbers)

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

As illustrated in the above example, we could sort numbers efficiently using Lists, an in-built data structure in Python.

Conclusion

In this chapter, we learned about data structures, their importance while developing large, maintainable systems while keeping the data organized and improving processing efficiency.

Strings

Lists