The + operator doesn’t just add two numbers, it can also “add” two strings! The process of combining two strings is called string concatenation. Performing string concatenation creates a brand new string comprised of the first string’s contents followed by the second string’s contents (without any added space in-between).

greeting_text = "Hey there!"
question_text = "How are you doing?"
full_text = greeting_text + question_text

# Prints "Hey there!How are you doing?"
print(full_text)

In this sample of code, we create two variables that hold strings and then concatenate them. But we notice that the result was missing a space between the two, let’s add the space in-between using the same concatenation operator!

full_text = greeting_text + " " + question_text

# Prints "Hey there! How are you doing?"
print(full_text)

Now the code prints the message we expected.

If you want to concatenate a string with a number you will need to make the number a string first, using the str() function. If you’re trying to print() a numeric variable you can use commas to pass it as a different argument rather than converting it to a string.

birthday_string = "I am "
age = 10
birthday_string_2 = " years old today!"

# Concatenating an integer with strings is possible if we turn the integer into a string first
full_birthday_string = birthday_string + str(age) + birthday_string_2

# Prints "I am 10 years old today!"
print(full_birthday_string)

# If we just want to print an integer 
# we can pass a variable as an argument to 
# print() regardless of whether 
# it is a string.

# This also prints "I am 10 years old today!"
print(birthday_string, age, birthday_string_2)

Using str() we can convert variables that are not strings to strings and then concatenate them. But we don’t need to convert a number to a string for it to be an argument to a print statement.