How to build a hash? This is the way if you know all your elements. 
%hash = (
  key1 => 'value1',
  key2 => 'value2',
  key3 => 'value3',
);

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But how can I build a hash if I dont know how much data or what kind of data will be read out of a file for example.   How to "push" unknown quatities of data into a hash?   Thank you very much.

janitored by ybiC: Minor format cleanup, including balanced <code> tags around snippet

In reply to How to build a hash? by Anonymous Monk

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