First Steps

Python Syntax Basics

Learn some Python syntax basics

We have already learnt that you can name a variable as you wish.

These are all valid variable names:

num
a_b
_num
num_
NUM
num123
nUm

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However, there are certain restrictions.

A variable name cannot start with a number. Let's see what happens if we try:

1_num = 1
print(1_num)

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Output

Python will also not accept any special characters like .-+:,;()/#*'"? in your variable names. They are reserved for other functionalities.

Also, be aware that variable names are case sentive.

The following are 2 different variables.

num=10
NUM=5
print(num)
print(NUM)

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Output

What will be the output?

num_ONE = 1
print(num_ONE)

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What will be the output?

num?one = 1
print(num?one)

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Another important aspect of the Python syntax is indentation.

Indentation refers to the whitespace at the beginning of a code line.

num=10
  num_with_indentation=10

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Your Python program will throw an error if it encounters unexpected whitespace at the beginning of a code line. Let's see what happens if we use unnecessary indentation:

  num_with_indentation=10
print(num_with_indentation)

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Output

What will be the output?

num = 0
  print(num)

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