Lesson 2: Python vs PHP: Main Syntax Differences

Instead of telling you all Python syntax features, let's save some time and look only at the main differences between Python and PHP languages.

Here's the first code example in both Python and PHP.

Python

"""
This is a code comment.
Multi-line comment.
"""
 
a = 5
 
if a > 5:
    print('Bigger than 5')  # This is inline comment
elif a >= 0:
    print('In between 0 and 5')
else:
    print('Negative')

PHP

/*
    This is a code comment.
    Multi-line comment.
*/
 
$a = 5;
 
if ($a > 5) {
    echo 'Bigger than 5'; // This is inline comment
} elseif ($a >= 0) {
    echo 'In between 0 and 5';
} else {
    echo 'Negative';
}

See the key differences? Based on this example and more examples below, let's list those differences.

1. End of Statement

• Python: The end of the statement is a new line
• PHP: Requires a semicolon ; at the end of each statement.

# Python: no semicolon
print('Bigger than 5')

// PHP: with semicolon
echo 'Bigger than 5';

2. Begin/End of Blocks

• Python: Uses indentation (whitespace) and colons : to indicate the beginning and end of code blocks.
• PHP: Uses curly braces {} to define code blocks.

# Python: ":" instead of curly braces
if a > 5:
    print('Bigger than 5')
    print('No, really bigger')
print('This is outside of IF-statement')

// PHP: curly braces
if ($a > 5) {
    echo 'Bigger than 5';
    echo 'No, really bigger';
}
echo 'This is outside of IF-statement';

3. Variable Declaration and Types

Both Python and PHP are dynamically typed languages, so you don't need to specify the data type explicitly.

Also, in Python, you don't need a $ sign for variables.

# Python
a = 5
if a > 5:
    print('Bigger than 5')

// PHP
$a = 5;
if ($a > 5) {
    echo 'Bigger than 5';
}

However, the languages have different "level of strictness" about data types.

PHP Example (loosely typed):

Conversions between types are often handled automatically.

$num = '10';
$result = $num + 5;

PHP automatically converts the $num string to a number for the addition.

Python (strongly typed):

Type conversions are more strict. The language enforces type constraints, and you must explicitly convert between different types. This example throws a TypeError Exception:

num = '10'
result = num + 5

TypeError: can only concatenate str (not "int") to str

To avoid this error, the num variable must be converted to an integer before explicitly adding it.

num = '10'
result = int(num) + 5

4. String Concatenation: "+" vs "."

Python: Uses the + operator for concatenation.

name = 'John'
message = 'Hello, ' + name

PHP: Uses the . operator for concatenation.

$name = 'John';
$message = 'Hello, ' . $name;

Python also has other syntax options for concatenation and formatting strings, like f-strings, we will talk about it in the next lesson about data types.

5. Conditional Statements: Parentheses

Python: you don't need parentheses ( and ) for conditions.

if a > 5:
    print('Bigger than 5')

PHP: Parentheses are required.

if ($a > 5) {
    echo 'Bigger than 5';
}

Notice: you actually can use the (condition) syntax in Python, but it is advised only for complex conditions if it improves readability or alters the order, like (a or b) and c.

6. Conditional Statements: Elif / Elseif

Python: uses the elif to check multiple conditions in sequence:

if a > 5:
    print('Bigger than 5')
elif a >= 0:
    print('In between 0 and 5')

PHP: uses the elseif instead:

if ($a > 5) {
    echo 'Bigger than 5';
} elseif ($a >= 0) {
    echo 'In between 0 and 5';
}

7. Logical Operators

Some operators from PHP are named differently in Python.

Specifically, the logical operators && and || are called and and or in Python. Similarly, the logical negation operator ! is named not in Python.

if a > 5 and b < 10:
    print('Case 1')
elif not (a < 0 or b < 0):
    print('Case 2')

8. Code Comments

You probably already saw this in the very first example, but I am repeating it, just in case.

Python: Single-line comments start with #.

# This is a single-line comment
 
a = 5  # This is a single-line comment

In Python, there is no specific syntax for creating multi-line, like /* ... */. However, you can achieve the same effect by using triple-quoted (multi-line) strings often used as docstrings.

"""
This is a multi-line comment in Python.
You can use triple-quoted strings to write
comments spanning multiple lines.
"""

Alternatively, you can have subsequent single-line comments.

# This is a multi-line comment in Python.
# You can use the # character at the beginning
# of each line to create comments spanning multiple lines.

PHP: Single-line comments start with //, and multiline comments use /* */.

/*
    This is
    multi-line comment
*/
 
echo 'Hi'; // This is inline comment

So, these are the most important syntax differences so you would understand the Python code when reading/writing it.