3.4 Print concatenated strings

In Python, you can concatenate strings using several methods. Each method has its own use case, but for simple string concatenation, using the + operator or formatted string literals (f-strings) are typically the most straightforward and readable. In the next section we will also explain how to use print() with F-strings which is the preferred way to format strings in Python 3.6+.

Syntax:

Here's a summary of the basic syntax for using the + operator to concatenate strings. 

# Basic concatenation
new_string = string1 + string2

# With additional characters
new_string = string1 + " " + string2

# Multiple strings
new_string = string1 + " " + string2 + " " + string3

 

Example 3.4.1 - Basic concatenation example to demonstrate the usage of + operator with strings.

print("Now I know how to concatenate " + "strings.")

Example 3.4.1 - Output 

Now I know how to concatenate strings.

 

Example 3.4.2 - Concatenation example with variables. 

str1 = "Hello"
str2 = "World"
result = str1 + " " + str2
print(result)

Example 3.4.2 - Output

Hello World

Example 3.4.2 - Explanation

  1. Here, two variables str1 and str2 are assigned the string values "Hello" and "World", respectively.

  2. The + operator is used to concatenate (combine) the strings.

    • First, str1 + " " is evaluated. This concatenates the string "Hello" with a single space character " ", resulting in the intermediate string "Hello ".
    • Then, "Hello " + str2 is evaluated. This concatenates the intermediate string "Hello " with str2 (which is "World"), resulting in the final string "Hello World".

  3. The resulting concatenated string "Hello World" is assigned to the variable result.

  4. The print function outputs the value of result to the console, which is "Hello World".

 

Example 3.4.3 - Concatenating multiple strings. You can concatenate multiple strings by chaining the + operator: 

# Define multiple strings
string1 = "Hello"
string2 = "beautiful"
string3 = "World"

# Concatenate all strings with spaces in between
result = string1 + " " + string2 + " " + string3

# Print the result
print(result)

Example 3.4.3 - Output

Hello beautiful World

Example 3.4.3 - Explanation

This is very similar to Example 3.4.2 but we're just chaining the + operator to add more strings in one final string.

 

In summary, the + operator takes two strings and combines them into a new string. If you concatenate multiple strings, you can chain the + operator to add each part sequentially. This method is straightforward and readable for simple concatenation tasks.

 

 

Exercise 3.4.1 - Create a Python program that asks the user for their first name and their favorite color. Then, use the + operator to concatenate these two pieces of information into a sentence and print the sentence. The sentence should be in the format:

"[First name]'s favorite color is [color]."

 

Exercise 3.4.1 - Model Answer - Make sure to work out the exercise before checking the model answer.