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erlangerlang-shell

Removing trailing ok from io:format in Erlang

I am building a simple tic tac toe program in Erlang. I pass the board as a string to io:format("123\n456\n789\n") and want to see:

123
456
789

But in the Erlang shell io:format("123\n456\n789\n") prints this:

123
456
789
ok

Is there a way to output to the console without the trailing ok?

Solution

  • The ok is there to tell you that the call worked. The spec for the function io:format specifies this.

    The real problem here is that you are seeing a mixture of the erlang terminal, and whatever is comming from stdout - stdout is printing the numbers, and the erlang terminal is giving back the ok.

    if you were writing a script using escript, the ok stratement will not be printed to standart output - you should simply think of the console as an interactive interpreter.

    As a side note the easiest way to output:

    123
456
789

    Would be 

    1> 123. 456. 789.
123
456
789