[erlang-questions] Erlang term to ASCII

Loïc Hoguin <>
Fri Feb 7 20:25:12 CET 2014

Str = io_lib:format("~9999999999999999999999999p", [Data])


On 02/07/2014 07:17 PM, Brandon Clark wrote:
> I have 2 production systems, one Erlang and one not, both maintaining
> copies of a large, deeply-nested Erlang data structure.  I need to set
> up a monitoring script to confirm that both systems are holding
> identical copies of the data structure.
> The non-Erlang system is holding an ASCII rendering of the data
> structure.  Computing an MD5 sum of this string is easy.  If I can get
> the Erlang system to convert its data structure to a string, I can have
> it compute an MD5 sum as well and the monitoring is simply a matter of
> comparing hashes.
> I'm stuck on the process of converting the Erlang term to a string.
> Str = io_lib:format("~p", [Data])
> gives me what I want, except that it includes newlines and indentation
> that I can't expect the non-Erlang system to have.
> Str = io_lib:format("~w", [Data])
> eliminates the newlines and indentation but renders the textual
> components of Data as lists of integers, guaranteeing the result won't
> match the non-Erlang system.
> So the question is, how do I get a "~p"-style rendering of an
> arbitrarily-large Erlang term /without/ newlines and indentation?
> Thank you!
> ~Brandon Clark
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Loïc Hoguin

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