文件里怎么引用變量

hisongy

123.sql內(nèi)容：select userid, msisdn, testertype, dst_testertype, oper_date from statuser.dw_to_up_result where oper_date = $GDATE

#!/usr/bin/perl
use strict;
use File::Basename;

my $GDATE=20160815;
my @fileContent;
my $fileString;

代碼：
    open INFILE, "<123.sql" || die "can't open $123.sql  !";

    @fileContent = <INFILE>;
    chomp(@fileContent);
    $fileString = join " ",@fileContent;
    print "$fileString";


    #while(<INFILE>
    #{
    #    print "$_";
    #}
close INFILE;
輸出結(jié)果 怎么才能引用$GDATE的值

stanley_tam

這樣？

1. #!/usr/bin/perl
   
2. use strict;
   
3. use File::Basename;
   
4. 
   
5. my $GDATE=20160815;
   
6. my @fileContent;
   
7. my $fileString;
   
8. 
   
9. open INFILE, "<123.sql" || die "can't open $123.sql  !";
   
10. 
    
11. @fileContent = <INFILE>;
    
12. chomp(@fileContent);
    
13. $fileString = join " ",@fileContent;
    
14. 
    
15. my $string;
    
16. $fileString = qq{\$string = "$fileString"};
    
17. eval $fileString;
    
18. print $string;
    
19. 
    
20. close INFILE;
    
21. 
    
22. __END__

復(fù)制代碼

sunzhiguolu

回復(fù) 2# stanley_tam
大師, 有個(gè)地方不明白 還請(qǐng)指點(diǎn)下:

#!/usr/bin/perl -w
use strict;

my $GDATE = '20160815';
while (<DATA>){
    my $line = qq ("$_");
    # eval $line;
}

__DATA__
select userid, msisdn, testertype, dst_testertype, oper_date from statuser.dw_to_up_result where oper_date = $GDATE

這種雙層嵌套雙引號(hào)的情況, 是個(gè)啥意思? 好像還必須是這樣, 不然就不行! (知道您老人家厲害, 簡(jiǎn)單點(diǎn)解釋就行, 謝謝)

   

stanley_tam

qq相當(dāng)于雙引號(hào)，后面的符號(hào)成對(duì)就可以了，用起來比下面這樣方便。

1. $fileString = "\$string = \"$fileString\"";

復(fù)制代碼

回復(fù) 3# sunzhiguolu


   

sunzhiguolu

回復(fù) 4# stanley_tam
\"$fileString\" 這個(gè)雙引號(hào)的作用能解釋下嗎, 謝謝.

   

stanley_tam

加了引號(hào)變量$fileString的值如下，這樣才是一個(gè)合法的perl語(yǔ)句。如果沒有引號(hào)，會(huì)報(bào)語(yǔ)法錯(cuò)誤的。

1. $string = "select userid, msisdn, testertype, dst_testertype, oper_date from statuser.dw_to_up_result where oper_date = $GDATE"

復(fù)制代碼

回復(fù) 5# sunzhiguolu


   

RE_HASH

$>  cat 123.sql |perl -npe '$GDATE="2016-08-18"; s/\$(\w+)/${$1}/g;'