A couple of suggestions. The following uses a substituation and removes the index from the rest of the data (i.e. the original data is changed).

$data_hash{$1}= $str if $str =~ s/(\d+)\|//;
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This uses matches the index and remaing data without altering the original.

$data_hash{$1}= $2 if $str =~ /(\d+)\|(.*)$/;
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I have used a conditional to assess the validity of the assignment beforehand. This is useful for data processing where the quality of the data is variable.