Can not handle Categorical in FAMD

I am using the latest version of Pandas and Prince. When I run the following example it does not work

df = pd.DataFrame( {‘variable_1’: [4, 5, 6, 7, 11, 2, 52], ‘variable_2’: [10, 20, 30, 40, 10, 74, 10], ‘variable_3’: [100, 50, 30, 50, 19, 29, 20], ‘color’: [‘red’, ‘blue’, ‘green’, ‘blue’, ‘red’, ‘red’, ‘blue’] })

df[‘color’]=df[‘color’].astype(‘category’) model = prince.FAMD( n_components = 2, copy = True, check_input = True, engine = ‘auto’, random_state = 1 ) model.fit(df)

ValueError: Not all columns in "Categorical" group are of the same type

I have also analyzed the reason why it occurs. When it call fit of mfa it checks whether it is categorical or not by the following code:

   for name, cols in sorted(self.groups.items()):
        all_num = all(pd.api.types.is_numeric_dtype(X[c]) for c in cols)
        all_cat = all(pd.api.types.is_string_dtype(X[c]) for c in cols)
        if not (all_num or all_cat):
            raise ValueError('Not all columns in "{}" group are of the same type'.format(name))

This was ok for earlier version of pandas. But now all_cat = all(pd.api.types.is_string_dtype(X[c]) for c in cols) this part does not works for Categorical data but only for object data.

So above part probably need to be corrected by following:

   for name, cols in sorted(self.groups.items()):
        all_num = all(pd.api.types.is_numeric_dtype(X[c]) for c in cols)
        all_obj= all(pd.api.types.is_string_dtype(X[c]) for c in cols)
        all_cat= all(pd.api.types.is_categorical_dtype(X[c]) for c in cols)
        if not (all_num or all_obj or all_cat):
            raise ValueError('Not all columns in "{}" group are of the same type'.format(name))

Am I right ?

[xosxos]

Same issue here with pandas 1.2.4 and prince 0.7.1

If someone is wondering, a temporary fix is to switch from dtype category to dtype object

df['color'] = df['color'].astype('object')

[vilhelmp]

Nice solution. After implementing it, I got an exception due to the for-loop directly after this in mfa.py.

You referenced this in your issue: https://github.com/MaxHalford/prince/blob/988f7fe01b6e4c9476517d1939f5fe0e13deb158/prince/mfa.py#L45-L52

I implemented your fix (important to keep self.all_nums_[name] = all_num), and got a new exception referencing the for-loop after this, here: https://github.com/MaxHalford/prince/blob/988f7fe01b6e4c9476517d1939f5fe0e13deb158/prince/mfa.py#L54-L75

The problem is that when running FAMD self.all_nums_ is a dictionary with only ‘Numerical’ as key, if I understand the code correct. However self.groups was created in famd.py which is a dictionary with both ‘Numerical’ and ‘Categorical’ as keys, so when it tries to run the check if self.all_nums_[name] with name as Categorical it throws a KeyError exception since it only has ‘Numerical’ in keys.

I changed if self.all_nums_[name]: to if name =='Numerical':

This however is only a quick fix, and probably not a robust way of fixing it.