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This article mainly introduces what the Perl pattern matching options are, which can be used for reference by interested friends. I hope you can learn a lot after reading this article.

Brief introduction of Perl mode

The Perl pattern refers to the characters of a specific sequence found in the string, contained by the backslash: / def/ is the Perl pattern def. Its use, such as combining the function split, divides the string into multiple words with a Perl pattern: @ array=split (/ /, $line).

Perl pattern matching options

Option description

G matches all possible Perl schemas

I ignore case

M treats strings as multiple lines

O assign a value only once

S treats the string as a single line

X ignore whitespace in Perl mode

1. Match all possible Perl modes (g option)

@ matches= "balata" = ~ / .a / Gbomaches.com ("ba", "la", "ta")

Matching loops:

While ("balata" = ~ / .a / g) {

$match=$&

Print ("$match\ n")

}

The result is:

Ba

La

Ta

When option g is used, the function pos can be used to control the offset of the next match:

$offset=pos ($string)

Pos ($string) = $newoffset

2. Ignore case (I option) example

/ de/i matches de,dE,De and DE.

3. Treat a string as multiple lines (m option)

In this case, the ^ symbol matches the beginning of a string or the beginning of a new line; the $symbol matches the end of any line.

4. perform a variable replacement example only once

$var=1; $line=; while ($var

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