String Interpolation in Swift + Calculation Tip #swift #iosdevelopment #programming

Added: 2026-05-28

[00:00:00]Let's define a few new variables. So, we're going to say friends is equal to three.

[00:00:06]Let extra guests equal to two.

[00:00:09]And a friends string is going to say friends were invited.

[00:00:17]And right here, we want to include the value of the number of friends. In this case, three. But, if we just write this friends constant over here, then we're going to get friends friends. All right, let me print this.

[00:00:28]But, we don't want it to say friends. We want the value of our friends constant to be displayed instead. For that, we put a backslash and a set of parentheses. And inside here, we can pass in our friends constant. Now, when we run it, we'll get three friends were invited. We could even do a floating point calculation this way. So, let's say let total guests equal and then the same thing as before, a backslash parentheses, and we'll say friends plus extra guests.

[00:00:57]Total people are coming.

[00:01:01]And now, instead of printing this friends string, we can print out the number of total guests. And when we run this, we get five total people are coming. And in case it's not clear, the way that we got five over here is because it did 3 + 2. So, the value of friends plus the value of extra guests inside this pair of parentheses. This method of including a variable inside a string is called string interpolation.

[00:01:23]Let me just write that out here.

[00:01:24]Interpolation.

[00:01:26]So, in summary, we can include the value of a constant or a variable inside a string using string interpolation.