This post is for someone who’s never coded before. We’re gonna go from zero what a variable is, what an “if” does, what a loop is, and why indentation matters in Python. No prior knowledge needed.

What you need

  • Python installed on your computer (python.org — get the latest 3.x).
  • A way to run code: either a simple text file saved as something.py that you run from the terminal, or an editor like VS Code / PyCharm.

If you prefer to simply follow along without installing anything, that is completely fine. You can run Python directly in your browser using an online interpreter such as online-python.com It allows you to write and execute Python code instantly without any setup.

To run a file locally: open a terminal in the folder where your .py file is and type:

python yourfilename.py

That’s it for setup. Rest is just writing code and running it.

Variables

A variable is a name that holds a value. You set it once and can use it later.

x = 1

This single line is saying: I’m setting x to 1. So whenever we use x in the code, it means 1 (until we change it).

We can use that name to do stuff:

x = 1
print(x)   # prints 1
x = 5
print(x)   # now it prints 5

So: variable = a box with a name. You put a value in it and can read or change it.

Conditionals (if)

Sometimes you only want to do something when a condition is true. That’s what if is for.

x = 1
if x == 1:
    print("x is one!")

Here we’re setting x to 1. The second line is checking if x is 1 and if so, it runs the print message. If x was something else (e.g. 2), that print would never run.

  • if = “only do the next block when this is true”
  • == = “is equal to” (comparing two things)
  • The line under if that runs when the condition is true has to be indented (we’ll get to that in a second).

So: if the condition is true, run the indented code. Otherwise skip it.

Indentation (why spaces/tabs matter in Python)

In a lot of languages you use curly braces { } to show “this code belongs to the if” or “this is inside the loop”. In Python we don’t. We use indentation the spaces (or tab) at the start of a line.

Whatever is indented under an if (or under a loop) belongs to that if or loop. So:

if x == 1:
    print("this runs when x is 1")
    print("this too, same block")
print("this always runs, it's not inside the if")

If you forget to indent, Python will complain. So: indent = “this line is part of the thing above it”. Keep it consistent (e.g. always 4 spaces).

Loops what they are

A loop is code that runs over and over until a certain condition is met (or until we’ve gone through a list a set number of times).

Simple analogy: The loop keeps rolling the dice until the result is 6. So the condition that makes us roll again is “dice is not 6”. That’s what a loop is repeat something until a condition is satisfied.

We’ll look at two kinds: while and for.

While loop

A while loop runs while a condition is true. When the condition becomes false, we stop.

import random
dice = 0
while dice != 6:
    dice = random.randint(1, 6)   # roll 1–6
    print("Rolled:", dice)
print("We got a 6, we're done!")

So: while “dice is not 6”, keep rolling and printing. When we get 6, we leave the loop and run the last line.

For loop

A for loop is often used to “go through” a range of numbers or a list, one by one.

In other languages you might see something like:

  • Start with i = 0
  • Keep going while i < n (i is below n)
  • After each run, do i++ (increase i by 1)

So that one line is saying: I’m setting i to 0; then “i < n” means “if it’s below n, keep going”; and we keep increasing i until the threshold is met. The rest of the logic inside the loop can get more complex, but that’s the idea of the loop itself.

In Python we usually write it like this:

n = 5
for i in range(n):
    print(i)

This prints 0, 1, 2, 3, 4. So i takes each value in that range, one after the other. Same idea: we’re “looping” through a set of values.

If we’re looping through a list:

fruits = ["apple", "banana", "cherry"]
for f in fruits:
    print(f)

So: a for loop = “do this block once for each item (or each number in a range)”.

Putting it together

  • Variables — names that hold values (x = 1).
  • Conditionals — run code only when something is true (if x == 1:).
  • Indentation — in Python, what’s indented under an if or loop belongs to it.
  • Loops — repeat code until a condition is met (while) or for each item in a range/list (for).

That’s the very basics. From here you can start writing small scripts, then look up things like lists, functions, and reading input. If something here was confusing, re-read that section and try changing the examples (e.g. change x to 2 and see what happens). Messing with the code is the best way to get it. Don’t be afraid to make mistakes and run failed codes part of learning.