比较两个文件时，如何跳过（忽略）空白行？

Question

我正在对两行文本文件ref.txt（参考）和log.txt进行比较。但是任何一个文件中可能会有任意数量的空白行，我想忽略它们;我怎么能做到这一点？

ref.txt

one 

two 


three 



end 

log.txt的

one 
two 
three 
end 

会有输出没有不正确的日志行，在log.txt与ref.txt匹配等字样。

我喜欢什么伪代码来完成：

while (traversing both files at same time) { 
    if ($l is blank line || $r is blank line) { 
     if ($l is blank line) 
      skip to next non-blank line 
     if ($r is blank line) 
      skip to next non-blank line 
    } 
    #continue with line by line comparison... 
} 

我当前的代码：

use strict; 
use warnings; 

my $logPath = ${ARGV [0]}; 
my $refLogPath = ${ARGV [1]} my $r; #ref log line 
my $l;         #log line 

open INLOG, $logPath or die $!; 
open INREF, $refLogPath or die $!; 

while (defined($l = <INLOG>) and defined($r = <INREF>)) { 
    #code for skipping blank lines? 
    if ($l ne $r) { 
     print $l, "\n";    #Output incorrect line in log file 
     $boolRef = 0;     #false==0 
    } 
} 

Answer 1

您可以通过比较这正则表达式跳过空白行：

next if $line =~ /^\s*$/ 

这将匹配任何可能构成空行的空格或换行符。

Answer 2

您可以循环找到的每一行，每一时间：

while(1) { 
    while(defined($l = <INLOG>) and $l eq "") {} 
    while(defined($r = <INREF>) and $r eq "") {} 

    if(!defined($l) or !defined($r)) { 
     break; 
    } 

    if($l ne $r) { 
     print $l, "\n"; 
     $boolRef = 0; 
    } 
} 

Answer 3

man diff 

diff -B ref.txt log.txt 

Answer 4

# line skipping code 
while (defined($l=<INLOG>) && $l =~ /^$/) {} # no-op loop exits with $l that has length 

while (defined($r=<INREF>) && $r =~ /^$/) {} # no-op loop exits with $r that has length 

Answer 5

如果你是一个Linux平台上，使用：

diff -B ref.txt log.txt 

的-B选项导致的变化只需插入或删除空白行即可忽略

Answer 6

这种方式似乎对我来说是最“类似perl”的。没有花哨的循环或任何东西，只是啜泣的文件和grep出空行。

use warnings; 

$f1 = "path/file/1"; 
$f2 = "path/file/2"; 

open(IN1, "<$f1") or die "Cannot open file: $f1 ($!)\n"; 
open(IN2, "<$f2") or die "Cannot open file: $f2 ($!)\n"; 

chomp(@lines1 = <IN1>); # slurp the files 
chomp(@lines2 = <IN2>); 

@l1 = grep(!/^\s*$/,@lines1); # get the files without empty lines 
@l2 = grep(!/^\s*$/,@lines2); 

# something like this to print the non-matching lines 
for $i (0 .. $#l1) { 
    print "[$f1 $i]: $l1[$i]\n[$f2 $i]: $l2[$i]\n" if($l1[$i] ne $l2[$i]); 
}