Perl Learning - 13 (m//, /i, /s, /x, ^$, \b)
发布时间：2020-12-15 21:02:21 所属栏目：大数据 来源：网络整理
导读：/patten/ is a default style of RE,it's actually m/patten/. Only use / the 'm' can be missing,otherwise 'm' must be there. ? m{patten} m|patten| m(patten) m[patten] m#patten# m*patten* m%patten% ? If we want use '^http://' as a patten,it's
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/patten/ is a default style of RE,it's actually m/patten/.
Only use / the 'm' can be missing,otherwise 'm' must be there.
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m{patten}
m|patten| m(patten) m[patten] m#patten# m*patten* m%patten%
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If we want use '^http://' as a patten,it's better not use '/'
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m{^http://} is good,otherwise we must write /^http:///
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There're some symbol called 'flag' can control the matching of patten,such as /i /s /x
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/i makes patten case insensitive.
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print "Would you like to play a game? ";
chomp($_=<STDIN>); if(/yes/i){ ?print "In that case,I recommend that you go bowling.n"; }
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/s makes '.' match any character including "n".
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$_="I saw Barneyndown at the bowling alleynwith frednlast night.n";
if(/Barney.*fred/s){ ?print "That string mentions fred after Barney!n"; }
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/x makes space characters can be added into patten,just fit for human reading. The #comments can also added in patten with /x
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/ -? d+ /.? d* /x
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/
?-??# 0 or 1 '-' ?d+?# 1 or more number ?.??# 0 or 1 '.' ?d*?# 0 or more number /x
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/i /s /x can be used together,the order makes no difference.
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if(/barney.*fred/is){
?print "That string mentions Fred after Barney!n"; }
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^ matches the beginning of string,$ matches the end of string including "n",/^fred$/ matches "fred" and "fredn"
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b matches the edge of "words","words" in Perl means w+ that is [A-Za-z0-9_]+
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Patten operates $_ be default,=~ makes it operate other strings.
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my $some_other="I dream of betty rubble.";if($some_other=~/brub/){?print "Hey,there's the rub.n";}
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