使用Perl中散列哈希数组解析CSV文件 [英] Parsing a CSV file using array of hash of hashes in Perl
问题描述
我有这种形式的CSV数据：
Sl.No，Label，Type1，Type2 ...
1，label1，Y，N，N ...
2，label2，N，Y，Y ...
...
其中Y和N表示是否将相应的标签打印到文件。
while（< $ fh>）{＃刷新CSV档案
$ filter = $ _;
chomp $ filter;
$ filter =〜tr / \r // d;
if（$。== 1）{
@fieldNames = split，，$ filter;
}
else {
@fields = split，，$ filter;
$ numCustomers = scalar（@fields） - 2;
push @labels，$ fields [2];
for（$ i = 0; $ i <$ numCustomers; $ i ++）{
for（$ j = 0; $ j< scalar（@labels） ; $ j ++）{
$ customer [$ i] [$ j] = $ fields [2 + $ i];
}
$ custFile =customer。 $ i。 _external.h;
open（$ fh1，>，$ custFile）或die无法为客户$ i创建外部头文件;
}
}
}
for（$ i = 0; $ i< scalar（@labels）; $ i ++）{
for（$ j = 0; $ j< $ numCustomers; $ j ++）{
$ Hash {$ fieldNames [2 + $ i]} - > {$ labels [$ i] } = $ customer [$ j] [$ i];
push @aoh，％Hash; ＃散列散列
}
}
my @headerLines = read_file（$ intFile）; ＃读取内部文件，并将CSV文件中未标记为
＃N的那些行仅复制到
＃到外部文件。
＃遍历每个哈希的元素，只有当值为'Y'时打印标签
foreach my $ headerLine（@headerLines）{
chomp $ headerLine;
for $ i（0 .. $＃aoh）{
for my $ cust1（排序键％{$ aoh [$ i]}）{#HERE
for my $ reqLabel1（keys％{$ aoh [$ i] {$ cust1}}）{
print$ cust1，$ reqLabel1：$ aoh [$ i] { $ cust1} {$ reqLabel1} \\\
;
if（$ aoh [$ i] {$ cust1} {$ reqLabel1} eqY）{
for（$ j = 0; $ j< $ numCustomers; $ j ++）{
$ req [$ j] [$ i] = $ reqLabel1;
}
}
else {
for（$ j = 0; $ j< $ numCustomers; $ j ++）{
$ nreq [$ j] [$ i] = $ reqLabel1;
}
}
}
}
if（grep {$ headerLine =〜/ $ _ /} @nreq）{
next; ＃不要在外部文件中打印此行
}
else {
print $ fh1 $ headerLine。 \\\
; #print外部文件中的这一行
}
}
}
这会引用不能使用字符串Type1作为哈希REF，引用标记为#HERE的行。
我试图在任何地方转储数据结构，但我不知道这是从哪里来的。
任何见解都将不胜感激。
我收到了反馈，表示使用 Text :: CSV 将是一个更好的解决方案。
确定，你的问题通过 Text :: CSV 。
但你的问题其实是这样的：
push @aoh，％Hash; ＃散列散列
这不会创建一个哈希数组。从％Hash 中提取所有元素（除了配对的键和值之外，没有特定顺序），并将它们插入到 @aoh
code> push @aoh，\％Hash;
或者：
push @aoh，{％Hash};
我不是很清楚，因为你重用％Hash ，所以你可能会得到重复。这最好由 use strict; 使用警告; 来正确处理你的哈希值。
I have CSV data in this form:
Sl.No, Label, Type1, Type2...
1, "label1", Y, N, N...
2, "label2", N, Y, Y...
...
Where "Y" and "N" denote whether the corresponding label is to be printed to a file or not.
while ( <$fh> ) { #Reading the CSV file
$filter = $_;
chomp $filter;
$filter =~ tr/\r//d;
if ( $. == 1 ) {
@fieldNames = split ",", $filter;
}
else {
@fields = split ",", $filter;
$numCustomers = scalar(@fields) - 2;
push @labels, $fields[2];
for ( $i = 0; $i < $numCustomers; $i++ ) {
for ( $j = 0; $j < scalar(@labels); $j++ ) {
$customer[$i][$j] = $fields[ 2 + $i ];
}
$custFile = "customer" . $i . "_external.h";
open( $fh1, ">", $custFile ) or die "Unable to create external header file for customer $i";
}
}
}
for ( $i = 0; $i < scalar(@labels); $i++ ) {
for ( $j = 0; $j < $numCustomers; $j++ ) {
$Hash{ $fieldNames[ 2 + $i ] }->{ $labels[$i] } = $customer[$j][$i];
push @aoh, %Hash; #Array of hashes
}
}
my @headerLines = read_file($intFile); # read the internal file, and copy only
# those lines that are not marked with
# "N" in the CSV file to the external file.
# iterate over elements of each hash and print the labels only if value is 'Y'
foreach my $headerLine (@headerLines) {
chomp $headerLine;
for $i ( 0 .. $#aoh ) {
for my $cust1 ( sort keys %{ $aoh[$i] } ) { #HERE
for my $reqLabel1 ( keys %{ $aoh[$i]{$cust1} } ) {
print "$cust1, $reqLabel1 : $aoh[$i]{$cust1}{$reqLabel1}\n";
if ( $aoh[$i]{$cust1}{$reqLabel1} eq "Y" ) {
for ( $j = 0; $j < $numCustomers; $j++ ) {
$req[$j][$i] = $reqLabel1;
}
}
else {
for ( $j = 0; $j < $numCustomers; $j++ ) {
$nreq[$j][$i] = $reqLabel1;
}
}
}
}
if ( grep { $headerLine =~ /$_/ } @nreq ) {
next; #Don't print this line in the external file
}
else {
print $fh1 $headerLine . "\n"; #print this line in the external file
}
}
}
This complains "Cannot use string Type1 as a hash REF", referring to the line marked as #HERE.
I've tried dumping data structures everywhere, but I'm not sure where this cropped up from.
Any insights would be appreciated.
I have received feedback that using Text::CSV would be a better solution. How would it reduce the need to use nested data structures?
Ok, your problem gets a lot easier with Text::CSV. I would suggest looking at a rewrite, or reasking your question framing it as such.
But your problem is actually this:
push @aoh, %Hash; #Array of hashes
That doesn't create an array of hashes at all. That extracts all the elements from %Hash (in no particular order, aside from keys and values being paired) and inserts them into @aoh.
You probably want:
push @aoh, \%Hash;
Or perhaps:
push @aoh, { %Hash };
I'm not entirely clear, because you're reusing %Hash, so you may get duplication. This is best dealt with by use strict; use warnings; and lexically scoping your hashes correctly.
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