What does %S mean in PHP, HTML or XML?

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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", ...

string-literals xml html php
5 Answers

The printf() or sprintf() function writes a formatted string to a variable. Here is the Syntax:

sprintf(format,arg1,arg2,arg++)

format:

  • %% - Returns a percent sign
  • %b - Binary number
  • %c - The character according to the ASCII value
  • %d - Signed decimal number (negative, zero or positive)
  • %e - Scientific notation using a lowercase (e.g. 1.2e+2)
  • %E - Scientific notation using a uppercase (e.g. 1.2E+2)
  • %u - Unsigned decimal number (equal to or greater than zero)
  • %f - Floating-point number (local settings aware)
  • %F - Floating-point number (not local settings aware)
  • %g - shorter of %e and %f
  • %G - shorter of %E and %f
  • %o - Octal number
  • %s - String
  • %x - Hexadecimal number (lowercase letters)
  • %X - Hexadecimal number (uppercase letters)

arg1:

  • The argument to be inserted at the first %-sign in the format string..(Required.)

arg2:

  • The argument to be inserted at the second %-sign in the format string. (Optional)

arg++:

  • The argument to be inserted at the third, fourth, etc. %-sign in the format string (Optional)

Example 1:

$number = 9;
$str = "New York";
$txt = sprintf("There are approximately %u million people in %s.",$number,$str);
echo $txt;

This will output:

There are approximately 9 million people in New York.

The arg1, arg2, arg++ 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.

Note: If there are more % signs than arguments, you must use placeholders. A placeholder is inserted after the % sign, and consists of the argument- number and "\$". Let see another Example:

Example 2

$number = 123;
$txt = sprintf("With 2 decimals: %1\$.2f
<br>With no decimals: %1\$u",$number);
echo $txt;

This will output:

With 2 decimals: 123.00
With no decimals: 123

Another important tip to remember is that:

With printf() and sprintf() functions, escape character is not backslash '\' but rather '%'. Ie. to print '%' character you need to escape it with itself:

printf('%%%s%%', 'Nigeria Naira');

This will output:

%Nigeria Naira%

Feel free to explore the official PHP Documentation

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