Regular Expression Meta-character Digit "d"
What is regular expression meta-character Digit "d"?
Explanation
In regular expression, the meta-character Digit "d" is used to match any numeric character.
<?php
$str = "hdhdh87544II";
$rslt = ereg_replace("[[:digit:]]","A",$str);
echo $rslt;
echo "n<br>n";
?> Result :
hdhdhAAAAAII
In the above example the pattern "d{5}(-d{4})?$/", first part "d{5}" matches a string with exactly "5" digits and the second part is a sub pattern "(-d{4})?$" matches a "-" along with exactly "4" digits, since the "?" is used for the subpattern it may or may not occur, "$" specifes to check the subpattern at the end of the string.
#! C:programfilesperlbinperl
print "content-type: text/htmlnn";
$name= "-23";
if ($name =~ m/^d+$/)
{print "It's a positive number!";}
else
{print "It's a negative number!";} Result :
It's a negative number!
In the above example a positive number is checked for to match, since a negative number is given the condition is false, so it print's the message.
PHP Example:
<?php
$str = "hdhdh87544II";
$rslt = ereg_replace("[[:digit:]]","A",$str);
echo $rslt;
echo "n<br>n";
?>
hdhdhAAAAAII
In the above example the pattern "d{5}(-d{4})?$/", first part "d{5}" matches a string with exactly "5" digits and the second part is a sub pattern "(-d{4})?$" matches a "-" along with exactly "4" digits, since the "?" is used for the subpattern it may or may not occur, "$" specifes to check the subpattern at the end of the string.
Perl Example:
#! C:programfilesperlbinperl
print "content-type: text/htmlnn";
$name= "-23";
if ($name =~ m/^d+$/)
{print "It's a positive number!";}
else
{print "It's a negative number!";}
It's a negative number!
In the above example a positive number is checked for to match, since a negative number is given the condition is false, so it print's the message.
