format
built-in function
format
is a built-in function to format a string. It takes first argument as format string and the rest of the arguments as values to format. It returns a formatted string.
What can it format?
format
can format any data type
Format string
The format string is a string that contains a placeholders. and the placeholders are replaced with the values passed as arguments.
Placeholders
Placeholders are curly brackets like {}
and this curly bracket will be replaced with the values passed as arguments. Also the placeholders can contain a number to specify the index of the argument to use. The index starts from 0.
Examples
In this example, the first placeholder {}
will be replaced with the first argument passed to the format
function, and the second placeholder {0}
contains a number 0
which is the index of the first argument passed to the format
function, so the second placeholder will be replaced with the first argument passed to the format
function.
~main<argc><argv>{<
formatted_string = format<"{} {0}"><"Hello, World!">;
println<formatted_string>;
>}
Output:
Hello, World! Hello, World!
In this example, the first placeholder {}
will be replaced with the first argument passed to the format
function, and the second placeholder {}
will be replaced with the second argument passed to the format
function.
~main<argc><argv>{<
formatted_string = format<"Hi {} you are from {}"><"Jhon"><"USA">;
println<formatted_string>;
>}
Output:
Hi Jhon you are from USA
Errors
format
function will throw an error if the format string contains a placeholder with a number that is greater than the number of arguments passed to the format
function. Also it will throw an error if the format string contains a placeholder with invalid index. For example, if the format string contains a placeholder with a number that is less than 0.