You can definitely use a variable in the string example that you have shown, in the following manner:

my_name = "Melanie"
Output = "My name is " + my_name + "."
print(Output)

My name is Melanie.

This is the easy way, but not the most elegant.

In the above example, I have used 3 lines and created 2 variables (my_name and Output)

However, I can get the same output using just one line of code and without creating any variables, using format()

print("My name is {}.".format("Melanie"))

My name is Melanie.

Curly braces {} are used as placeholders, and the value we wish to put in the placeholders are passed as parameters into the format function.

If you have more than one placeholder in the string, python will replace the placeholders by values, in order.

Just make sure that the number of values passed as parameters to format(), is equal to the number of placeholders created in the string.

For example:

print("My name is {}, and I am {}.".format("Melanie",26))

My name is Melanie, and I am 26.

There are 3 different ways to specify placeholders and their values:

Type 1:

print("My name is {name}, and I am {age}.".format(name="Melanie", age=26))

Type 2:

print("My name is {0}, and I am {1}.".format("Melanie",26))

Type 3:

print("My name is {}, and I am {}.".format("Melanie",26))

Additionally, by using format() instead of a variable, you can:

1. Specify the data type, and
2. Add a formatting type to format the result.

For example:

print("{0:^7} has completed {1:.3f} percent of task {2}".format("Melanie",75.765367,1))

Melanie has completed 75.765 percent of task 1.

I have set the data type for the percentage field to be a float, with 3 decimals, and given a character length of 7 to the name, and center-aligned it.

The alignment codes are:

' < ' :left-align text

' ^ ' :center text

' > ' :right-align

The format() method is helpful when you have multiple substitutions and formattings to perform on a string.