Primary Case: CSV (with primary key) to Hash of Hashes

Text::CSV::Hashify turns that kind of CSV file into one big hash of hashes. Elements of this hash are keyed on the entries in the designated primary key field and the value for each element is a hash reference of all the data in a particular database record (including the primary key field and its value).

Secondary Case: CSV (lacking primary key) to Array of Hashes

In this case, while an individual record can be turned into a hash, the CSV file as a whole cannot accurately be turned into a hash of hashes. As a fallback, Text::CSV::Hashify can, upon request, turn this into an array of hashes. In this case, you will not be able to look up a particular record by its primary key. You will instead have to know its index position within the array (which is equivalent to knowing its record number in the original CSV file minus 1).

Interfaces

Use the functional interface when all you want is to turn a CSV file with a primary key field into a hash of hashes.

Use the object-oriented interface for any more sophisticated manipulation of the CSV file. This includes:

• Text::CSV options

  Access to any of the options available to Text::CSV, such as use of a separator character other than a comma. Note: Much of the time you will not need any of the Text::CSV options. Text::CSV::Hashify is focused on reading CSV files, whereas Text::CSV is focused on both reading and writing CSV files. Some Text::CSV options, such as "eol", are unlikely to be needed when using Text::CSV::Hashify. Hence, you should be very selective in your use of Text::CSV options.

• Limit number of records

  Selection of a limited number of records from the CSV file, rather than slurping the whole file into your in-memory hash.

• Array of hash references format

  Probably better than the default hash of hash references format when the CSV file has no field able to serve as a primary key.

• Metadata

  Access to the list of fields, the list of all primary key values, the values in an individual record, or the value of an individual field in an individual record.

Note: On the recommendation of the authors/maintainers of Text::CSV, Text::CSV::Hashify will internally always set Text::CSV's "binary => 1" option.

"new()"

• Purpose

  Text::CSV::Hashify constructor.

• Arguments

      $obj = Text::CSV::Hashify->new( {
          file        => '/path/to/file.csv',
          format      => 'hoh', # hash of hashes, which is default
          key         => 'id',  # needed except when format is 'aoh'
          max_rows    => 20,    # number of records to read; defaults to all
          ... # other key-value pairs as appropriate from Text::CSV
      } );
      

  Single hash reference. Required element is:

• Return Value

  Text::CSV::Hashify object.

• Comment

"all()"

• Purpose

  Get a representation of all data found in a CSV input file.

• Arguments

      $hash_ref   = $obj->all; # when format is default or 'hoh'
      $array_ref  = $obj->all; # when format is 'aoh'
      

• Return Value

  Reference representing all data records in the CSV input file. In the default case, or if you have specifically requested "format =" 'hoh'>, the return value is a hash reference. When you have requested "format =" 'aoh'>, the return value is an array reference.

• Comment

  In the default ("hoh") case, the return value is equivalent to that of "hashify()".

"fields()"

• Purpose

  Get a list of the fields in the CSV source.

• Arguments

      $fields_ref = $obj->fields;
      

• Return Value

  Array reference.

• Comment

  If any field names are duplicate, you will not get this far, as "new()" would have died.

"record()"

• Purpose

  Get a hash representing one record in the CSV input file.

• Arguments

      $record_ref = $obj->record('value_of_key');
      

  One argument. In the default case ("format => 'hoh'"), this argument is the value in the record in the column serving as unique key.

  In the "format => 'aoh'" case, this will be index position of the data record in the array. (The header row will be at index 0.)

• Return Value

  Hash reference.

"datum()"

• Purpose

  Get value of one field in one record.

• Arguments

      $datum = $obj->datum('value_of_key', 'field');
      

  List of two arguments: the value in the record in the column serving as unique key; the name of the field.

• Return Value

  Scalar.

"keys()"

• Purpose

  Get a list of all unique keys found in the input file.

• Arguments

      $keys_ref = $obj->keys;
      

• Return Value

  Array reference.

• Comment

  If you have selected "format => 'aoh'" in the options to "new()", the "keys" method is inappropriate and will cause your program to die.

Text-CSV and Text-CSV_XS

Text-CSV-Slurp

Text-CSV-Auto