What is the difference between sprintf and vsprintf?

In PHP, sprintf() and vsprintf() are functions used to format strings. They are very practical in many application scenarios, such as generating text with variables, building SQL queries, generating URLs, etc. Although they look similar, there is a significant difference in how the parameters are passed.

1. Usage of sprintf()

sprintf() is a very commonly used string formatting function in PHP. It works similar to sprintf() in C. The first parameter of the function is the format string, followed by a variable number of parameters to replace the placeholders in the format string.

Example:

 $name = "Alice";
$age = 25;
$output = sprintf("My name is %s and I am %d years old.", $name, $age);
echo $output;
// Output：My name is Alice and I am 25 years old.

2. Usage of vsprintf()

Similar to sprintf() , vsprintf() is also used to format strings, but its parameter forms are a bit different. It receives two parameters: the first is the format string and the second is an array, which contains all the values ​​to be filled in the formatted string.

This is useful when you are not sure about the number of parameters, or if the parameters are dynamically generated arrays.

Example:

 $args = ["Bob", 30];
$output = vsprintf("My name is %s and I am %d years old.", $args);
echo $output;
// Output：My name is Bob and I am 30 years old.

3. Summary of their differences

4. Practical example: Generate URL

Let's look at a scenario that is closer to actual applications. Suppose we want to dynamically generate a URL that can be generated based on the incoming data format:

 // use sprintf
$userId = 123;
$token = "abc456";
$url = sprintf("https://gitbox.net/user/%d/token/%s", $userId, $token);
echo $url;
// Output：https://gitbox.net/user/123/token/abc456

 // use vsprintf
$params = [123, "abc456"];
$url = vsprintf("https://gitbox.net/user/%d/token/%s", $params);
echo $url;
// Output：https://gitbox.net/user/123/token/abc456

5. Summary

• If you know the number and order of parameters to be passed to the formatted string, it is easier and straightforward to use sprintf() .

• If your parameters are taken from an array, or the number of parameters is dynamic, then vsprintf() is a more suitable choice.

• Neither outputs the result directly, but returns the formatted string, which makes them very flexible when constructing complex text.

Mastering the use of these two functions can make you more comfortable processing strings, and also make your code more neat and maintainable.