perl下关于文件读写，hash统计频数并排序的总结

很少用到perl，这次用了一把，特意记录一下关于文件读写和hash统计频数并排序的总结：

1.文件读写

perl下读写文件非常简单：，首先是读：

#打开文件

open(FILE_NAME, $_)||die "can't open part-m file";

一行一行读出来并处理：

while (<FILE_NAME>)

{

chomp;

print $_,"\n";

###

处理

###

}

然后是写：

#创建写的文件：不存在就创建，存在就清空然后再写；如果将">"改成">>"就是追加的写

open(OUTFILE1_LIST, ">$resultpath.\\SpecificResult.txt")||die "can't open file SpecificResult.txt!";

#一行行写文件

print OUTFILE1_LIST ("$lineTxt\n");

#写完关闭

close(OUTFILE1_LIST);

2.哈希统计频数并排序

#初始化

my %hash=();

#统计每个词的个数

$hash{$lineTxt}++;

#按value值排序

my @keys = sort { $hash{$b} <=> $hash{$a} } keys %hash; #@key里头存的是按哈希值的数值大小排序后的键

#按key值排序

my @keys = sort { $b <=> $a} keys %hash; #@key里头存的是按哈希键的数值大小排序后的键

foreach(@keys)

{

print OUTFILE2_LIST ("$_"."\t"."$hash{$_}"."\n");

}

下面是我写的用来解析现网数据并排序的源代码：

#!/usr/bin/perl -W

##################

# File:

# Author:

# License:

use strict;

use warnings;

use encoding 'gbk'; # 系统默认编码为GBK

use open IN=>':encoding(utf8)'; # 读入文件时认为数据按UTF-16编码，自动根据BOM头判断是LE还是BE

use Encode;

use File::Path;

use Tie::File;

#读取外部传入的待解析现网数据的存放目录路径

my $dirpath="";

if(@ARGV == 1)

{

$dirpath = $ARGV[0];

}else

{

print "< .pl > <待解析现网数据的存放目录路径>\n";

exit(0);

}

print "dir path: ${dirpath}\n";

#$dirpath="E:\\video_network_data";

my @filearray=(); #存放每个part-m文件的绝对路径

my $filecount = 0; #存放part-m文件的个数

###### 遍历文件夹 #####

sub parse_env {

my $path = $_[0];

my $subpath;

my $handle;

if (-d $path) {#当前路径是否为一个目录

if (opendir($handle, $path)) {

while ($subpath = readdir($handle)) {

if (!($subpath =~ m/^\.$/) and !($subpath =~ m/^(\.\.)$/)) {

my $p = $path."/$subpath";

if (-d $p) {

parse_env($p);

}

else {

if($p=~m/part-m/) {

push(@filearray,$p);

$filecount++;

}

}

}

}

}

closedir($handle);

}

return $filecount;

}

my %hash=();

my $filenum=parse_env $dirpath;

if($filenum > 0) #存在part-m文件

{

print "There are $filenum part-m files!!","\n";

my $resultpath=$dirpath."\\parse-result";

mkdir($resultpath) unless(-d $resultpath); #创建目录，准备存放解析结果

open(OUTFILE1_LIST, ">$resultpath.\\SpecificResult.txt")||die "can't open file SpecificResult.txt!";

open(OUTFILE2_LIST, ">$resultpath.\\FrequencyResult.txt")||die "can't open file FrequencyResult.txt!";

foreach(@filearray)

{

#print $_,"\n";

open(FILE_NAME, $_)||die "can't open part-m file";

while (<FILE_NAME>)

{

my @strlist=split("\t",$_);

if(($#strlist+1)>=4)

{

my $lineTxt=$strlist[3];

print OUTFILE1_LIST ("$lineTxt\n");

$hash{$lineTxt}++;

}

}

}

my @keys = sort { $hash{$b} <=> $hash{$a} } keys %hash; #sort the hash table

foreach(@keys)

{

print OUTFILE2_LIST ("$_"."\t"."$hash{$_}"."\n");

}

close(OUTFILE1_LIST);

close(OUTFILE2_LIST);

print "-------FINISH!!!--------\n";

}