This example counts the words in a file and writes a list with words and the coresponding count

 $ include "seed7_05.s7i";       # Standard Seed7 library
   include "scanfile.s7i";       # Import the getSimpleSymbol function

 const type: wordHash is hash [string] integer;

 const proc: main is func
   local
     var wordHash: numberOfWords is wordHash.EMPTY_HASH;
     var string: symbol is "";
   begin
     while not eof(IN) do
       symbol := getSimpleSymbol(IN);
       if symbol in numberOfWords then
         incr(numberOfWords[symbol]);
       else
         numberOfWords @:= [symbol] 1;
       end if;
     end while;
     for symbol range sort(keys(numberOfWords)) do
       writeln(symbol rpad 20 <& " " <& numberOfWords[symbol]);
     end for;
   end func;

The hash 'numberOfWords' is used to count the words (=symbols). Symbols are read from the standard input 'IN' with 'getSymbol(IN)'. Every 'symbol' is checked with the 'in' operator for presence in 'numberOfWords'. The '@:=' statement inserts the value '1' to 'numberOfWords' with the key 'symbol'. The 'keys' function delivers an unordered array of keys from 'numberOfWords'. The resulting array string is sorted with the 'sort' function.