appy group targets on existing weight variable

[nitsrek]

currently used workaround

adj_w_vec = pd.Series()
countries = [153, 75, 230 ,210, 82, 1]
for c in countries:
    w_vec = dataset[dataset.take({'country': c}), 'weight']
    valid_counts = dataset['weight'].count()
    if not c == 230:
        ratio = 1/float(len(countries)) * w_vec
    else:
        # add factor if weighted and unweighted bases differ
        ratio = (1212.0/1208.1) * (1/float(len(countries)) * w_vec)
    scale_factor = len(w_vec.index) / float(valid_counts)
    ratio = ratio / scale_factor
    adj_w_vec = adj_w_vec.append(ratio).dropna()
dataset['w_all'] = adj_w_vec