hashesAndArrays.rb

# a ist ein eindimensionales array
def removeCell(a,k)
  a = a[0,k] + a[k+1,a.size-1];
end;

#p(removeCell([1,2,3,4], 3));
# [1,2,3];

#p("Hallo Welt"[6,4]);

# a ist Array
# und k der Index des zu verwendenen Schlüssels in a[i] für alle i von 0 bis a.size-1
def arrayToHash(a,k)
  
  hash = {};
  for i in 0..a.size-1 do
    key = a[i][k];
    #puts("Key: " + key.to_s());
    # value entspricht Array `a` ohne den Wert an Index `k`
    value = removeCell(a[i],k);
    #print("Value: ");
    #p(value);
    
    # einfügen in hash
    # Variante 1:
    # hash[key] = value;
    # Variante 2:
    # hash.[]=(key,value);
    # Variante 3:
    hash.store(key,value);
  end;
  return hash;

end;


def addCell(a,k,value)
  return(a[0,k] + [value] + a[k,a.size-k]);
end;

#a = [1,2,3];
#p(a[0,0]);
#p(a[0,a.size]);

def hashToArray(h,k)

  array = [];
  for key in h.each_key
    valueArray = h[key];
    newValue = addCell(valueArray,k,key);
    array = array + [newValue];
  end;
  return array;

end;


a = [["Mustermann","Max",1234],["Exemplaris","Emilie",7890]];
#p(a);
#p(arrayToHash(a,2));

#h = {1234=>["Mustermann","Max"], 7890=>["Exemplaris","Emilie"]};
#p(h);
#p(hashToArray(h,0));
#p(arrayToHash(hashToArray(h,1),1) == h);
#p(hashToArray(arrayToHash(a,2),2) == a);

# filter auf array

def filter_with_array(a)
  
  b = []; # neues Array
  for i in 0..a.size-1 do
    if yield a[i] then
      b = b + [a[i]];
    end;
  end;
  return b;
  
end;

h = [10,11,12,3];
newH = filter_with_array(h) {|var| var < 10};
#p(newH);

# Aufruf von lambda-Funktionen
#inc = lambda {|var| var + 1};
#p(inc.call(5));