ara_2_woe_iv_function

ara_2_woe_iv_function.py

def calculate_woe_iv(dataset, feature, target):
    lst = []
    for i in range(dataset[feature].nunique()):
        val = list(dataset[feature].unique())[i]
        lst.append({
            'Value': val,
            'All': dataset[dataset[feature] == val].count()[feature],
            'Good': dataset[(dataset[feature] == val) & (dataset[target] == 0)].count()[feature],
            'Bad': dataset[(dataset[feature] == val) & (dataset[target] == 1)].count()[feature]
        })
        
    dset = pd.DataFrame(lst)
    dset['Distr_Good'] = dset['Good'] / dset['Good'].sum()
    dset['Distr_Bad'] = dset['Bad'] / dset['Bad'].sum()
    dset['WoE'] = np.log(dset['Distr_Good'] / dset['Distr_Bad'])
    dset = dset.replace({'WoE': {np.inf: 0, -np.inf: 0}})
    dset['IV'] = (dset['Distr_Good'] - dset['Distr_Bad']) * dset['WoE']
    iv = dset['IV'].sum()
    
    dset = dset.sort_values(by='WoE')
    
    return dset, iv