Usage

There are two main functions providing fundamental functionality. The string_format() function is designed to return formatted string and the print_format() function prints the value immediately returning void.

Both functions take at least one argument which is the format specification and variadic arguments which can be positional arguments along with named arguments.

Formatting string and returning

Above shows examples of formatting a string specification with use of positional arguments.

Reference to the first positional argument.

use fmt\string_format;

$message = string_format('First, thou shalt count to {0}', 3);
Note
Positional arguments count from 0 even if they’re not passed as an argument at position 0 due to fact that first argument is always a format specification.

Implicit reference to positional arguments

use fmt\string_format;

$message = string_format('Bring me a {}', 'book');
Note
Without an argument position or it’s name the first {} is equivalent to {0}.
use fmt\string_format;

$message = string_format('From {} to {}', 5, 10);
Note
Without specifying further positions it’s the same as "From {0} to {1}".

References to named argument

use fmt\string_format;

$message = string_format('My quest is {name}', name: 'John');
use fmt\string_format;

$message = string_format(
    '{when:Y-m-d} is {temp:0.1f}°C and is {cond}',
    temp: 32, // (1)
    cond: 'sunny', // (2)
    when: new DateTimeImmutable('now'), // (3)
);
var_dump($message);
// string(23) "2020-08-20 is 32.0°C and is sunny."

  1. An integer is a scalar value and can be formatted as a decimal or integer.

  2. A string is a scalar and can be only formatter as a string.

  3. A DateTimeInterface family classes can be formatted using a {datetime-format}[datetime format].

Print formatted string

The print_format() function takes at least one argument which is the format specification and variadic arguments which can be positional arguments along with named arguments and prints formatted string just like the string_format() does.

use fmt\print_format;

print_format('Hello {}!', 'John');

Output:

Hello John!