perl 常用函数以及例子代码

abs
PERL 代码:
#!/usr/bin/perl?-w
#$result=abs(value);
#
@re=abs(-23);
print?"/@re/=abs/(/-23/)/;/n";
print?"/@re/=@re/n";?

array
PERL 代码:
#!/usr/bin/perl?-w
@num=qw(11?33?2?dd?0);
printf?"first:@num/n";
$name="dear";
@list=(1..12,"hello",$name,"hello?$name",4+6,1-2,2*3);
printf?"second:@list/n";
@a=(a..z,A..Z,-2.3..8.1);
printf?"three:@a/n";
printf?"four:next/n";
@b=(1,"world",@num);
printf?"third@b/n";
printf?"sixnext/n";
@c=@num;
printf?"sevre@c/n";?

atan2
PERL 代码:
#!/usr/bin/perl?-w
#retval=atan2(value1,value2);
#
sub?degress_to_radians?{
my?($degress)?=?@_;
my?($radians);11;
$radians?=?atan2(1,1)?*?$degress?/45;
}?

chdir
PERL 代码:
#!/usr/bin/perl?-w
#change?the?current?directory?.
chdir("/root");
$result=system("ls");
print?"$result/n";?

chomp AND chop
PERL 代码:
#!/usr/bin/perl?-w
use?strict;
my?@a="abcd";
print?"@a/n--chomp--/n";
chomp(@a);
print?"@a/n";
print?"---chop---/n";
my?@b="uiok";
print?"@b/n";
chop(@b);
print?"@b/n";?
在 预读Perl程序代码的时 候，也许你会发现Coder有时会用chop()函数来去掉<>输入的换行符"/n"，有时候使用chomp()函数。

??其 实上面的用法都可以达到预期的效果，但它们也有细微的差别。

?

chr
PERL 代码:
#!/usr/bin/perl?-w
#@char=chr(asciivalue);
#
@a=chr(97);
print?"@a/n";?

each
PERL 代码:
#!/usr/bin/perl?-w
#@pair=each(%assoc_array);
#
print?"/@pair/=each/(/%assoc/_array/)/;/n";
%array=(9,"first",2,"second");
@a=each(%array);
print?"@a/n";

%arrayA=(8,6,"second");
@b=each(%arrayA);
print?"@b/n";

%arrayB=(12,98,"second",66,"three","found");
@d=each(%arrayB);
@e=each(%arrayB);
@f=each(%arrayB);
print?"@d/n@e/n@f/n";?

eof
PERL 代码:
#!/usr/bin/perl?-w
while?($line?=?)?{
print?($line);
if?(eof)?{
print?("--?end?of?current?file?--/n");
}
}

eval PERL 代码: #!/usr/bin/perl?-w $print="print?(/"hello,world//n/");"; eval?($print); #run?as?perl?command.? foreach PERL 代码: #!/usr/bin/perl?-w @array=("how","do","you","do"?,?"fine"); foreach?$a(@array){ $a=~s/o/CHANGE/; print?"$a/n"; }; # open?(FILE,?"test03.pl"?); foreach?(?)?{ print?"$_"; }? fork PERL 代码: #!/usr/bin/perl?-w $result=fork(); if($result?==?0)?{ #this?is?the?child?process exit;?#this?is?terminates?the?child?process }else{ #this?is?the?parent?process }? forka PERL 代码: #!/usr/bin/perl?-w $child=fork(); print?"$child/n";? format PERL 代码: #!/usr/bin/perl?-w #file?:format # $~="myformat"; write; format?myformat= ======================== hello,the?world! ======================== .? getc AND die PERL 代码: #!/usr/bin/perl?-w open(FILE,"/etc/fstab")?or?die?"could?not?open?/etc/fstab:$!"; print?(getc(FILE),""); $a=getc(FILE); #chomp($a); print?"$a"; print?(getc(FILE)); print?(getc(FILE)."/n");? grep PERL 代码: #!/usr/bin/perl?-w #@foundlist?=?grep?(pattern,?@searchlist); # @list?=?("This",?"is",?"a",?"test"); @foundlist?=?grep(/^[tT]/,?@list); print?"@list/n@foundlist/n"; # #result::: #This?is?a?test #This?test? hash 引用: #!/usr/bin/perl -w %a=(1,"a","b",3,"c",4,"d",5,"e","f"); $b=$a{1}; print "$b/n"; # $a{2}="change"; $b=$a{2}; print "$b/n"; # @index=keys(%a); print "@index/n"; # @content=values(%a); print "@content/n"; # @d=%a; print "@d/n"; # delete $a{5}; @d=%a; print "@d/n"; # $i="a"; $j=1; delete ${$i}{$j}; @d=%a; print "@d/n"; hex PERL 代码: #!/usr/bin/perl?-w #16?format?to?10?format?number. #result=hex(16?format); # @a=hex(032); print?"@a/n";? index PERL 代码: #!/usr/bin/perl?-w #position=index(string,substring,position); # @re=index("1234567","123"); print?"@re/n"; @re=index("1234567","6","3"); print?"@re/n";? int PERL 代码: #!/usr/bin/perl?-w @a=int(2.39); print?"@a/n";? join PERL 代码: #!/usr/bin/perl?-w #join?(joinstr,list); # @a=("a","d"); print?"@a/n"; @b=join("#",@a); print?"@b/n";? keys PERL 代码: #!/usr/bin/perl?-w #@list=keys(%assoc_array); %NAME=(1,"mike","michael"); @readkey=keys(%NAME); print?"%NAME/n"; print?"@readkey/n";? kill PERL 代码: #!/usr/bin/perl?-w #kill(signal,proclist); #signal?==?signal?;example?9 #porclist?==?process?ID kill?(9,1617);? last PERL 代码: #!/usr/bin/perl?-w $a=12; print?"/$a/=$a/n"; while($a<25)?{ $a++; last?if?($a?==?20); print?"$a?"; } print?"/n";? lc PERL 代码: #!/usr/bin/perl?-w @a=lc("ABC"); print?"@a/n";? lcfirst PERL 代码: #!/usr/bin/perl?-w # #?result=lcfirst(string); @result=lcfirst("abcdefg"); print?"@result/n"; @a=lcfirst("ABCD"); print?"@a/n";? length PERL 代码: #!/usr/bin/perl?-w #num=length(string); # @num=length("abcdefg"); print?"@num/n";? log PERL 代码: #!/usr/bin/perl?-w #result=log(value); # $re=log(12); print?"/$re/=log/(12/)/;/n"; print?"/$re/=$re/n";? map PERL 代码: #!/usr/bin/perl?-w #@resultlist=map(expr,@list); # @list=(50,1000); print?"@list/n"; @result=map($_+1,@list); print?"@result/n"; print?"@list/n";? mkdir PERL 代码: #!/usr/bin/perl?-w #4000:?running?setup?user?ID. #2000:?running?setup?groupp?ID. #1000:?ease. #0400:?readable?with?own. #0200:?write?with?own. #0200:?can?running?with?own. #0040:?readable?group. #0020:?can?write?with?group. #0010:?can?running?with?group. #0004:?readable?with?all?user. #0002:?write?with?all?user. #0001;?running?with?all?user. mkdir("aka",0777)?or?die?"Could?not?creat?directory/n";? next PERL 代码: #!/usr/bin/perl?-w $a=18; while($a<23){ $a++; next?if?($a==20); print?"$a?"; } print?"$a/n";? oct PERL 代码: #!/usr/bin/perl?-w #8?OR?16?format?to?10?format #@result=oct(octnum); # @a=oct("013"); print?"@a/n"; @b=oct("0x1a"); print?"@b/n";? opendir ADN readdir AND closedir PERL 代码: #!/usr/bin/perl?-w opendir?(DIR,"/root")?or?die?"could?not?open?/root"; @dots=grep?{/^[^.]/?&&?-d?"/root/$_"?}?readdir(DIR); foreach?(@dots)?{ print?"$_/n"; } closedir?DIR;? ord PERL 代码: #!/usr/bin/perl?-w #@result=ord("char"); #print?a?character?ASCII?value. # use?strict; my?@a=ord("a"); print?"@a/n";? pipe PERL 代码: #!/usr/bin/perl?-w pipe(INPUT,OUTPUT); $result=fork(); if($result?!=?0){ #this?is?cht?parent?process. close(INPUT); print("Enter?a?line?of?input:/n"); $line=; print?OUTPUT?($line); }else{ #this?is?the?child?process. close?(OUTPUT); $line=; print($line); exit(0); } #pipe?as?shell?"?|?".? pop PERL 代码: #!/usr/bin/perl?-w #@element=pop(@array); # @array=("hello","the","dear"); print?"@array/n"; @element=pop(@array); print?"@array/n@element/n";? push PERL 代码: #!/usr/bin/perl?-w #push(@arrayvar,elements); # @array=("hello","free","world"); print?"@array/n"; push(@array,"my?dear"); print?"@array/n"; push(@array,"my?dear?too"); print?"@array/n";? redo PERL 代码: #!/usr/bin/perl?-w $a=15; while?($a<19){ $a++; print?"$a?"; redo?if?($a?==19); } print?"/n"; $a=15; while($a<=19){ $a++; print?"$a?"; redo?if?($a?==19); } print?"/n";? reverse PERL 代码: #!/usr/bin/perl?-w use?strict; print?"Enter?the?list?of?string:/n"; my?$a=0; my?$into; my?@test; while?(?$a<6)?{ chomp($into=); unshift(@test,"$into"); $a++?; } print?"@test/n"?; # my?@reverse=reverse(@test); print?"@reverse/n?"; my?@b; @b=reverse("a","d"); print?"@b/n";? rindex PERL 代码: #!/usr/bin/perl?-w #position?=rindex(string,substring.position); #from?right?to?left # @a=rindex("abcdefg","b"); print?"@a/n"; @a=rindex("abcdefg","e"); print?"@a/n";? shift PERL 代码: #!/usr/bin/perl?-w #element?=?shift?(@arrayvar); # @array=("a","998","ojjo","iu"); print?"@array/n"; @a=shift(@array); print?"@array/n@a/n";? shutdown 引 用: #Shuts down a socket connection in the manner indicated by HOW,which has the #same interpretation as in the system call of the same name. shutdown(SOCKET,0); # I/we have stopped reading data shutdown(SOCKET,1); # I/we have stopped writing data shutdown(SOCKET,2); # I/we have stopped using this socket sleep PERL 代码: #!/usr/bin/perl?-w @a=sleep?(3); print?("the?process?alerady?sleep?3?second/n"); print?"@a/n"; print?("return?value?is?NULL/n"); print?"/n";? sort PERL 代码: #!/usr/bin/perl?-w @a=sort("a",1,0); print?"@a/n";? splice PERL 代码: #!/usr/bin/perl?-w #@retval?=?splice?(@array,?slipelements,?length,?@newlist); #if?lenth=0;then?insert?a?element. # @array=("a","9","8","K","ok"); @a=splice?(@array,?2,?"Hello"); print?"@a/n";? split PERL 代码: #!/usr/bin/perl?-w #@list=split(parrern,sting,maxlength); # @text=("well","hello,the?world","how","do"); print?"@text/n"; @name=split(/,/,@text,2); print?"@name/n"; print?"@text/n"; $abc?=?"apile:fjkdfk:300:500:XXX:/bin/bash"; @abc?=?split(/:/,$abc); print?"@abc/n";? sprintf PERL 代码: #!/usr/bin/perl?-w #same?like?printf?,not?ouput?to?file,return?value?to?variable?. # $num=26; $outstr=sprintf("%d=%x?hexadecimal?or?%o?octal/n",$num,$num); print?($outstr);? sqrt PERL 代码: #!/usr/bin/perl?-w #retval=sqrt(value); #example #value?>?0; $result=sqrt(9); print?"/$result/=sqrt/(9/)/;/n/$result/=$result/n";? srand AND rand PERL 代码: #!/usr/bin/perl?-w #result=rand(num); # srand(); $re=rand(A); print?"$re/n";? system PERL 代码: #!/usr/bin/perl?-w #system()?;run?a?shell?commend. $result=system?"date"; $see=system("ls","/root"); print?"$result/n"; print?"$see/n"; $well=system?"'date'"; print?"$well/n"; @hello=("echo",world!"); system(@hello);? uc PERL 代码: #!/usr/bin/perl?-w @a=uc("abcd"); print?"@a/n";? unless PERL 代码: #!/usr/bin/perl?-w $a=12; unless?($a!=12){ print?"first:$a/n"; } unless($a==12){ print?"second:$a/n"; }? unlink PERL 代码: #!/usr/bin/perl?-w #unlink("filename"); unlink("/share/perl/test");? unpack PERL 代码: #!/usr/bin/perl?-w #@list?=?unpack?(packformat,?formatstr); # open?(CODEDFILE,?"/share/perl/function/aa")?|| die?"Can't?open?input?file"; open?(OUTFILE,?">outfile")?|| die?"Can't?open?output?file"; while?($line?=?)?{ $decoded?=?unpack("u",?$line); print?OUTFILE?($decoded); } close?(OUTFILE); close?(CODEDFILE);? unshift PERL 代码: #!/usr/bin/perl?-w #count?=?unshift?(@arrayver,?elements); # @array=("ui","ok","nb","li","well"); print?"@array/n"; @a=unshift(@array,"first"); print?"@array/n@a/n";? until PERL 代码: #!/usr/bin/perl?-w $a=12; until?(?$a==18)?{ $a++; print?"$a?"; } print?"/n";? values PERL 代码: #!/usr/bin/perl?-w #@list=values(%assoc_array); # print?"/@list/=values/(/%assoc/_array/)/;/n"; %NAME=(1,"michael"); @readval=values(%NAME); print?"@readval/n";? vec PERL 代码: #!/usr/bin/perl?-w #retval?=?vec?(vector,?index,?bits); # $vector?=?pack?("B*",?"11010011"); $val1?=?vec?($vector,?0,?4); $val2?=?vec?($vector,?1,?4); print?("high-to-low?order?values:?$val1?and?$val2/n"); $vector?=?pack?("b*",?4); print?("low-to-high?order?values:?$val1?and?$val2/n");? waitpid PERL 代码: #!/usr/bin/perl?-w #wait?for?a?sub_process,unit?the?sub_process?done. #procid?is?ID?of?sub_process #format?:?waitpid(procid,witflay); #example: $procid=fork(); if?($procid?==?0){ #this?is?the?child?porcess print?("this?line?is?printed?first/n"); exit(0); }else{ #this?is?the?parent?process waitpid($procid,0); print?("this?line?is?printed?last/n"); }? wantarray PERL 代码: #!/usr/bin/perl?-w #result=wantarray(); @array?=?&mysub(); $scalar?=?&mysub(); sub?mysub?{ if?(wantarray())?{ print?("true/n"); }?else?{ print?("false/n"); } }? while PERL 代码: #!/usr/bin/perl?-w use?strict; open(FILE,?"/etc/fstab"?); my?$line; while?(?$line=)?{ print?"$line"; }? umask PERL 代码: umask(0111);