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How do you combine variables in Python?

Published in Python Programming 4 mins read

You can combine variables in Python using several methods, including the + operator, the join() method, the % operator, the format() function, and f-strings (literal string interpolation). Each method serves different purposes and offers unique advantages depending on the data types and desired outcome.

Combining Variables Using the + Operator

The + operator is the most straightforward way to concatenate strings and add numerical values.

# String concatenation
string1 = "Hello"
string2 = "World"
combined_string = string1 + " " + string2  # Adds a space in between
print(combined_string)  # Output: Hello World

# Numerical addition
number1 = 10
number2 = 5
sum_of_numbers = number1 + number2
print(sum_of_numbers)  # Output: 15

Note: When using the + operator with mixed data types (e.g., a string and an integer), you'll need to explicitly convert the non-string variable to a string using the str() function.

age = 30
message = "My age is " + str(age)
print(message)  # Output: My age is 30

Combining Variables Using the join() Method

The join() method is specifically designed for concatenating strings within an iterable (e.g., a list or tuple). It's an efficient way to combine multiple strings into a single string.

words = ["This", "is", "a", "sentence."]
combined_sentence = " ".join(words) # The string before .join is what will separate the elements
print(combined_sentence)  # Output: This is a sentence.

Combining Variables Using the % Operator (String Formatting)

The % operator is an older method for string formatting. While still functional, it's generally recommended to use format() or f-strings for newer code.

name = "Alice"
age = 25
formatted_string = "My name is %s and I am %d years old." % (name, age)
print(formatted_string)  # Output: My name is Alice and I am 25 years old.
  • %s is a placeholder for a string.
  • %d is a placeholder for an integer.

Combining Variables Using the format() Function

The format() function provides a more versatile and readable way to format strings.

name = "Bob"
age = 40
formatted_string = "My name is {} and I am {} years old.".format(name, age)
print(formatted_string)  # Output: My name is Bob and I am 40 years old.

# You can also use index numbers to control the order:
formatted_string = "I am {1} years old and my name is {0}.".format(name, age)
print(formatted_string) # Output: I am 40 years old and my name is Bob.

# Or use keyword arguments:
formatted_string = "My name is {name} and I am {age} years old.".format(name="Charlie", age=35)
print(formatted_string) # Output: My name is Charlie and I am 35 years old.

Combining Variables Using f-strings (Literal String Interpolation)

F-strings, introduced in Python 3.6, offer a concise and readable way to embed expressions inside string literals. They are generally considered the most modern and convenient method.

name = "David"
age = 28
formatted_string = f"My name is {name} and I am {age} years old."
print(formatted_string)  # Output: My name is David and I am 28 years old.

# You can also perform calculations directly within the f-string:
x = 5
y = 2
result = f"The sum of {x} and {y} is {x + y}."
print(result) # Output: The sum of 5 and 2 is 7.

In summary, Python provides multiple ways to combine variables, each offering different levels of flexibility and readability. F-strings are generally recommended for modern Python development due to their conciseness and ease of use.

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