I'm looking at Webmonkey's PHP and MySql Tutorial, Lesson 2. I think it's a php literal. What does %s
mean? It's inside the print_f()
function in the while loops in at least the first couple of code blocks.
printf("<tr><td>%s %s</td><td>%s</td></tr>n", ...
From the documentation: d - the argument is treated as an integer, and presented as a (signed) decimal number. s - the argument is treated as and presented as a string.
The sprintf() function writes a formatted string to a variable. The arg1, arg2, ++ parameters will be inserted at percent (%) signs in the main string. This function works "step-by-step". At the first % sign, arg1 is inserted, at the second % sign, arg2 is inserted, etc.
with printf or sprintf characters preceded by the % sign are placeholders (or tokens). They will be replaced by a variable passed as an argument.
Example:
$str1 = 'best'; $str2 = 'world'; $say = sprintf('Tivie is the %s in the %s!', $str1, $str2); echo $say;
This will output:
Tivie is the best in the world!
Note: There are more placeholders (%s for string, %d for dec number, etc...)
Order:
The order in which you pass the arguments counts. If you switch $str1 with $str2 as
$say = sprintf('Tivie is the %s in the %s!', $str2, $str1);
it will print
"Tivie is the world in the best!"
You can, however, change the reading order of arguments like this:
$say = sprintf('Tivie is the %2$s in the %1$s!', $str2, $str1);
which will print the sentence correctly.
Also, keep in mind that PHP is a dynamic language and does not require (or support) explicit type definition. That means it juggles variable types as needed. In sprint it means that if you pass a "string" as argument for a number placeholder (%d), that string will be converted to a number (int, float...) which can have strange results. Here's an example:
$onevar = 2; $anothervar = 'pocket'; $say = sprintf('I have %d chocolate(s) in my %d.', $onevar, $anothervar); echo $say;
this will print
I have 2 chocolate(s) in my 0.
More reading at PHPdocs
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