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What's the difference between echo and printf?

BenMorel
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Tommy Arnold
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    -1: You really should read the documentation. There is a significant difference between the two: http://php.net/manual/en/function.echo.php and http://www.php.net/manual/en/function.printf.php. – Tieson T. Mar 02 '13 at 22:31
  • everything is in the doc, in addition of what Tieson T. linked, see http://www.php.net/manual/en/function.sprintf.php for examples of formats – tmuguet Mar 02 '13 at 22:33
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    Voted to reopen as this is the top result in google. – Tommy Arnold Jan 12 '18 at 19:08

2 Answers2

9

The main difference is that printf receives first a format string, with placeholders (those % signs you see), and can even accept some formatting parameters (like %2d, which would show 2 digits for a number).

Echo is, instead, just displaying the string. When you do "$i bar", the string is first expanded with the value of $i, and then sent to the echo function to be shown.

Alex Siri
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4

If you search the differences in any search engines, you'll get your answer. For example below is one use for printf:

You can use this function to format the decimal places in a number: 

$num = 2.12; 
printf("%.1f",$num); 

prints: 

2.1

And of course this is only just one use. Another good sample that i use is below:

If you are printing data in a "pre" tag, courier font, or otherwise non-variable length font (like a terminal), you might have use for printf's justify feature. 

$value1 = "31298";
$value2 = "98";

print "<pre>\n";
printf ("%'.-15.15s%'.6.6s\n", $heading1, $value1);
printf ("%'.-15.15s%'.6.6s\n", $heading2, $value2);
print "</pre>\n";
?>

And lots of other usage.

MIIB
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