How can I concatenate str and int objects in Python?

Concatenating a string and an integer in Python is a common task in programming. Here are three different ways to do it:

Using the str() function to convert the integer to a string

Example

In this method, we define a string called my_string and an integer called my_number. We use the str() function to convert my_number to a string, and then we concatenate the two strings using the + operator. Finally, we print out the resulting string.

my_string = "The answer is: "
my_number = 42

result = my_string + str(my_number)

print(result)

Output

The answer is: 42

Using f-strings

Example

In this method, we define a string called my_string and an integer called my_number. We use an f-string to insert the value of my_number into the string. We surround my_string and my_number with curly braces {} to tell Python to substitute the value of my_number for that expression in the resulting string. Finally, we print out the resulting string.

my_string = "The answer is: "
my_number = 42

result = f"{my_string}{my_number}"

print(result)

Output

The answer is: 42

Using string formatting

Example

In this method, we define a string called my_string that includes a placeholder %d for a decimal number. We then use the % operator to substitute the value of my_number for that placeholder in the resulting string. Finally, we print out the resulting string.

my_string = "The answer is: %d"
my_number = 42

result = my_string % my_number

print(result)

Output

The answer is: 42

Using join() method with a list comprehension

Example

In this method, we define a string called my_string and a list of integers called my_numbers. We use a list comprehension to convert each integer to a string using str(num). Then, we use the join() method to concatenate the string representation of each integer in the list with a comma and a space. Finally, we concatenate the resulting string with my_string and print out the final string.

my_string = "The numbers are: "
my_numbers = [1, 2, 3, 4]

result = my_string + ", ".join(str(num) for num in my_numbers)

print(result)

Output

The numbers are: 1, 2, 3, 4

Using string formatting with named placeholders

Example

In this method, we define a string called my_string that contains named placeholders {num_apples} and {num_oranges}. We then use the format() method to substitute the values of num_apples and num_oranges for those placeholders in the resulting string. We pass these values to the format() method as keyword arguments. Finally, we print out the resulting string.

my_string = "I have {num_apples} apples and {num_oranges} oranges."
num_apples = 5
num_oranges = 3

result = my_string.format(num_apples=num_apples, num_oranges=num_oranges)

print(result)

Output

I have 5 apples and 3 oranges.

Using f-strings with expressions

Example

In this method, we define an integer called num. We then use an f-string to insert expressions into the string using curly braces {}. We can perform arithmetic operations within these curly braces to generate dynamic values. In this example, we multiply num by 2 and insert the resulting value into the string, and also insert the value of num itself. Finally, we print out the resulting string.

num = 42

result = f"The answer is {num * 2}, not {num}."

print(result)

Output

The answer is 84, not 42.

We have thus seen that these examples are helpful in concatenating a str object and an int object.