Improve pretty printing of regression results

Pretty print categorical variables and show reference category

tests/test_regress.py

@@ -38,13 +38,13 @@ def test_regress_ols_ol11_4():
 	assert result.ftest().pvalue < 0.0005
 	assert result.rsquared == approx(0.7429, abs=0.0001)
 	
-	assert result.beta['Intercept'].point == approx(47.48, abs=0.01)
+	assert result.terms['(Intercept)'].beta.point == approx(47.48, abs=0.01)
-	assert result.pvalues['Intercept'] < 0.0005
+	assert result.terms['(Intercept)'].pvalue < 0.0005
-	assert result.beta['SoilPh'].point == approx(-7.86, abs=0.01)
+	assert result.terms['SoilPh'].beta.point == approx(-7.86, abs=0.01)
-	assert result.pvalues['SoilPh'] < 0.0005
+	assert result.terms['SoilPh'].pvalue < 0.0005
 	
-	assert result.beta['SoilPh'].ci_lower == approx(-10.15, abs=0.01)
+	assert result.terms['SoilPh'].beta.ci_lower == approx(-10.15, abs=0.01)
-	assert result.beta['SoilPh'].ci_upper == approx(-5.57, abs=0.01)
+	assert result.terms['SoilPh'].beta.ci_upper == approx(-5.57, abs=0.01)
 
 def test_regress_ols_ol13_5():
 	"""Compare yli.regress for Ott & Longnecker (2016) chapter 13.5"""
@@ -72,28 +72,28 @@ def test_regress_ols_ol13_5():
 	assert result.ftest().pvalue < 0.00005
 	assert result.rsquared == approx(0.8635, abs=0.0001)
 	
-	assert result.beta['Intercept'].point == approx(-10.63398, abs=0.00001)
+	assert result.terms['(Intercept)'].beta.point == approx(-10.63398, abs=0.00001)
-	assert result.pvalues['Intercept'] == approx(0.0766, abs=0.0001)
+	assert result.terms['(Intercept)'].pvalue == approx(0.0766, abs=0.0001)
-	assert result.beta['D'].point == approx(0.22760, abs=0.00001)
+	assert result.terms['D'].beta.point == approx(0.22760, abs=0.00001)
-	assert result.pvalues['D'] == approx(0.0157, abs=0.0001)
+	assert result.terms['D'].pvalue == approx(0.0157, abs=0.0001)
-	assert result.beta['T1'].point == approx(0.00525, abs=0.00001)
+	assert result.terms['T1'].beta.point == approx(0.00525, abs=0.00001)
-	assert result.pvalues['T1'] == approx(0.8161, abs=0.0001)
+	assert result.terms['T1'].pvalue == approx(0.8161, abs=0.0001)
-	assert result.beta['T2'].point == approx(0.00561, abs=0.00001)
+	assert result.terms['T2'].beta.point == approx(0.00561, abs=0.00001)
-	assert result.pvalues['T2'] == approx(0.2360, abs=0.0001)
+	assert result.terms['T2'].pvalue == approx(0.2360, abs=0.0001)
-	assert result.beta['S'].point == approx(0.00088369, abs=0.00000001)
+	assert result.terms['S'].beta.point == approx(0.00088369, abs=0.00000001)
-	assert result.pvalues['S'] < 0.0001
+	assert result.terms['S'].pvalue < 0.0001
-	assert result.beta['PR'].point == approx(-0.10813, abs=0.00001)
+	assert result.terms['PR'].beta.point == approx(-0.10813, abs=0.00001)
-	assert result.pvalues['PR'] == approx(0.2094, abs=0.0001)
+	assert result.terms['PR'].pvalue == approx(0.2094, abs=0.0001)
-	assert result.beta['NE'].point == approx(0.25949, abs=0.00001)
+	assert result.terms['NE'].beta.point == approx(0.25949, abs=0.00001)
-	assert result.pvalues['NE'] == approx(0.0036, abs=0.0001)
+	assert result.terms['NE'].pvalue == approx(0.0036, abs=0.0001)
-	assert result.beta['CT'].point == approx(0.11554, abs=0.00001)
+	assert result.terms['CT'].beta.point == approx(0.11554, abs=0.00001)
-	assert result.pvalues['CT'] == approx(0.1150, abs=0.0001)
+	assert result.terms['CT'].pvalue == approx(0.1150, abs=0.0001)
-	assert result.beta['BW'].point == approx(0.03680, abs=0.00001)
+	assert result.terms['BW'].beta.point == approx(0.03680, abs=0.00001)
-	assert result.pvalues['BW'] == approx(0.7326, abs=0.0001)
+	assert result.terms['BW'].pvalue == approx(0.7326, abs=0.0001)
-	assert result.beta['N'].point == approx(-0.01203, abs=0.00001)
+	assert result.terms['N'].beta.point == approx(-0.01203, abs=0.00001)
-	assert result.pvalues['N'] == approx(0.1394, abs=0.0001)
+	assert result.terms['N'].pvalue == approx(0.1394, abs=0.0001)
-	assert result.beta['PT'].point == approx(-0.22197, abs=0.00001)
+	assert result.terms['PT'].beta.point == approx(-0.22197, abs=0.00001)
-	assert result.pvalues['PT'] == approx(0.1035, abs=0.0001)
+	assert result.terms['PT'].pvalue == approx(0.1035, abs=0.0001)
 
 def test_regress_logit_ol12_23():
 	"""Compare yli.regress for Ott & Longnecker (2016) chapter 12.23"""
@@ -112,12 +112,12 @@ def test_regress_logit_ol12_23():
 	assert lrtest_result.dof == 2
 	assert lrtest_result.pvalue == approx(0.0191, rel=0.02)
 	
-	expbeta_fib = np.exp(result.beta['Fibrinogen'])
+	expbeta_fib = np.exp(result.terms['Fibrinogen'].beta)
 	assert expbeta_fib.point == approx(6.756, rel=0.01)
 	assert expbeta_fib.ci_lower == approx(1.007, rel=0.01)
 	assert expbeta_fib.ci_upper == approx(45.308, rel=0.02)
 	
-	expbeta_gam = np.exp(result.beta['GammaGlobulin'])
+	expbeta_gam = np.exp(result.terms['GammaGlobulin'].beta)
 	assert expbeta_gam.point == approx(1.169, abs=0.001)
 	assert expbeta_gam.ci_lower == approx(0.924, abs=0.001)
 	assert expbeta_gam.ci_upper == approx(1.477, abs=0.001)
@@ -133,14 +133,14 @@ def test_regress_penalisedlogit_kleinman():
 	result = yli.regress(yli.PenalisedLogit, df, 'Outcome', 'Pred', exp=False)
 	
 	assert result.dof_model == 1
-	assert result.beta['(Intercept)'].point == approx(-2.280389)
+	assert result.terms['(Intercept)'].beta.point == approx(-2.280389)
-	assert result.beta['(Intercept)'].ci_lower == approx(-2.765427)
+	assert result.terms['(Intercept)'].beta.ci_lower == approx(-2.765427)
-	assert result.beta['(Intercept)'].ci_upper == approx(-1.851695)
+	assert result.terms['(Intercept)'].beta.ci_upper == approx(-1.851695)
-	assert result.pvalues['(Intercept)'] < 0.0001
+	assert result.terms['(Intercept)'].pvalue < 0.0001
-	assert result.beta['Pred'].point == approx(5.993961)
+	assert result.terms['Pred'].beta.point == approx(5.993961)
-	assert result.beta['Pred'].ci_lower == approx(3.947048)
+	assert result.terms['Pred'].beta.ci_lower == approx(3.947048)
-	assert result.beta['Pred'].ci_upper == approx(10.852893)
+	assert result.terms['Pred'].beta.ci_upper == approx(10.852893)
-	assert result.pvalues['Pred'] < 0.0001
+	assert result.terms['Pred'].pvalue < 0.0001
 	
 	lrtest_result = result.lrtest_null()
 	assert lrtest_result.statistic == approx(78.95473)

yli/regress.py

@@ -103,7 +103,7 @@ class RegressionResult:
 		raw_result,
 		full_name, model_name, fit_method,
 		dep, nobs, dof_model, fitted_dt,
-		beta, pvalues,
+		terms,
 		llf, llnull,
 		dof_resid, rsquared, f_statistic,
 		exp
@@ -122,9 +122,8 @@ class RegressionResult:
 		self.dof_model = dof_model
 		self.fitted_dt = fitted_dt
 		
-		# Regression coefficients
+		# Regression coefficients/p values
-		self.beta = beta
+		self.terms = terms
-		self.pvalues = pvalues
 		
 		# Model log-likelihood
 		self.llf = llf
@@ -165,7 +164,7 @@ class RegressionResult:
 		"""
 		
 		# Get parameters required for AFBF
-		params = pd.Series({term.replace('[', '_').replace(']', '_'): beta.point for term, beta in self.beta.items()})
+		params = pd.Series({term.raw_name.replace('[', '_').replace(']', '_'): term.beta.point for term in self.terms.values()})
 		cov = self.raw_result.cov_params()
 		
 		# Compute BF matrix
@@ -240,12 +239,33 @@ class RegressionResult:
 		# Render coefficients table
 		out += '<table><tr><th></th><th style="text-align:center">{}</th><th colspan="3" style="text-align:center">(95% CI)</th><th style="text-align:center"><i>p</i></th></tr>'.format('exp(<i>β</i>)' if self.exp else '<i>β</i>')
 		
-		for term, beta in self.beta.items():
+		for term_name, term in self.terms.items():
-			# Exponentiate if requested
+			if isinstance(term, SingleTerm):
-			if self.exp:
+				# Single term
-				beta = np.exp(beta)
 				
-			out += '<tr><th>{}</th><td>{:.2f}</td><td style="padding-right:0">({:.2f}</td><td>–</td><td style="padding-left:0">{:.2f})</td><td style="text-align:left">{}</td></tr>'.format(term, beta.point, beta.ci_lower, beta.ci_upper, fmt_p(self.pvalues[term], html=True, nospace=True))
+				# Exponentiate beta if requested
+				beta = term.beta
+				if self.exp:
+					beta = np.exp(beta)
+				
+				out += '<tr><th>{}</th><td>{:.2f}</td><td style="padding-right:0">({:.2f}</td><td>–</td><td style="padding-left:0">{:.2f})</td><td style="text-align:left">{}</td></tr>'.format(term_name, beta.point, beta.ci_lower, beta.ci_upper, fmt_p(term.pvalue, html=True, nospace=True))
+			elif isinstance(term, CategoricalTerm):
+				# Categorical term
+				out += '<tr><th>{}</th><td></td><td style="padding-right:0"></td><td></td><td style="padding-left:0"></td><td></td></tr>'.format(term_name)
+				
+				# Render reference category
+				out += '<tr><td style="text-align:right;font-style:italic">{}</td><td>Ref.</td><td style="padding-right:0"></td><td></td><td style="padding-left:0"></td><td></td></tr>'.format(term.ref_category)
+				
+				# Loop over terms
+				for sub_term_name, sub_term in term.categories.items():
+					# Exponentiate beta if requested
+					beta = sub_term.beta
+					if self.exp:
+						beta = np.exp(beta)
+					
+					out += '<tr><td style="text-align:right;font-style:italic">{}</td><td>{:.2f}</td><td style="padding-right:0">({:.2f}</td><td>–</td><td style="padding-left:0">{:.2f})</td><td style="text-align:left">{}</td></tr>'.format(sub_term_name, beta.point, beta.ci_lower, beta.ci_upper, fmt_p(sub_term.pvalue, html=True, nospace=True))
+			else:
+				raise Exception('Attempt to render unknown term type')
 		
 		out += '</table>'
 		
@@ -273,13 +293,34 @@ class RegressionResult:
 		# Render coefficients table
 		table_data = []
 		
-		for term, beta in self.beta.items():
+		for term_name, term in self.terms.items():
-			# Exponentiate if requested
+			if isinstance(term, SingleTerm):
-			if self.exp:
+				# Single term
-				beta = np.exp(estimate)
 				
-			# Add some extra padding
+				# Exponentiate beta if requested
-			table_data.append([term + '  ', format(beta.point, '.2f'), '({:.2f}'.format(beta.ci_lower), '-', '{:.2f})'.format(beta.ci_upper), '  ' + fmt_p(self.pvalues[term], html=False, nospace=True)])
+				beta = term.beta
+				if self.exp:
+					beta = np.exp(beta)
+				
+				# Add some extra padding
+				table_data.append([term_name + '  ', format(beta.point, '.2f'), '({:.2f}'.format(beta.ci_lower), '-', '{:.2f})'.format(beta.ci_upper), '  ' + fmt_p(term.pvalue, html=False, nospace=True)])
+			elif isinstance(term, CategoricalTerm):
+				# Categorical term
+				table_data.append([term_name + '  ', '', '', '', '', ''])
+				
+				# Render reference category
+				table_data.append(['{}  '.format(term.ref_category), 'Ref.', '', '', '', ''])
+				
+				# Loop over terms
+				for sub_term_name, sub_term in term.categories.items():
+					# Exponentiate beta if requested
+					beta = sub_term.beta
+					if self.exp:
+						beta = np.exp(beta)
+					
+					table_data.append([sub_term_name + '  ', format(beta.point, '.2f'), '({:.2f}'.format(beta.ci_lower), '-', '{:.2f})'.format(beta.ci_upper), '  ' + fmt_p(sub_term.pvalue, html=False, nospace=True)])
+			else:
+				raise Exception('Attempt to render unknown term type')
 		
 		table2 = SimpleTable(data=table_data, headers=['', 'exp(β)' if self.exp else 'β', '', '\ue000', '', ' p'])  # U+E000 is in Private Use Area, mark middle of CI column
 		table2_text = table2.as_text().replace('    \ue000   ', '(95% CI)')  # Render heading in the right spot
@@ -293,6 +334,27 @@ class RegressionResult:
 		
 		return out
 
+class SingleTerm:
+	"""
+	A term in a RegressionResult which is a single term
+	
+	raw_name: The raw name of the term (e.g. in RegressionResult.raw_result data)
+	beta: An Estimate of the coefficient
+	pvalue: The p value
+	"""
+	
+	def __init__(self, raw_name, beta, pvalue):
+		self.raw_name = raw_name
+		self.beta = beta
+		self.pvalue = pvalue
+
+class CategoricalTerm:
+	"""A group of terms in a RegressionResult corresponding to a categorical variable"""
+	
+	def __init__(self, categories, ref_category):
+		self.categories = categories
+		self.ref_category = ref_category
+
 def regress(
 	model_class, df, dep, formula, *,
 	nan_policy='warn', exp=None
@@ -328,8 +390,40 @@ def regress(
 		result.exp = exp
 		return result
 	
+	# Process terms
+	terms = {}
+	
 	confint = result.conf_int()
-	beta = {t: Estimate(b, confint[0][t], confint[1][t]) for t, b in result.params.items()}
+	
+	for raw_name, raw_beta in result.params.items():
+		beta = Estimate(raw_beta, confint[0][raw_name], confint[1][raw_name])
+		
+		# Rename terms
+		if raw_name == 'Intercept':
+			# Intercept term (single term)
+			term = '(Intercept)'
+			terms[term] = SingleTerm(raw_name, beta, result.pvalues[raw_name])
+		elif '[T.' in raw_name:
+			# Categorical term
+			term = raw_name[:raw_name.index('[T.')]
+			category = raw_name[raw_name.index('[T.')+3:raw_name.index(']')]
+			
+			if term.startswith('C('):
+				term = term[2:-1]
+			
+			# Add a new categorical term if not exists
+			if term not in terms:
+				# Try to guess the ref_category
+				# FIXME: This is a VERY brittle implementation!!
+				ref_category = sorted(df[term].unique())[0]
+				
+				terms[term] = CategoricalTerm({}, ref_category)
+			
+			terms[term].categories[category] = SingleTerm(raw_name, beta, result.pvalues[raw_name])
+		else:
+			# Single term
+			term = raw_name
+			terms[term] = SingleTerm(raw_name, beta, result.pvalues[raw_name])
 	
 	# Fit null model (for llnull)
 	if hasattr(result, 'llnull'):
@@ -346,7 +440,7 @@ def regress(
 		result,
 		'Logistic Regression' if model_class is sm.Logit else '{} Regression'.format(model_class.__name__), model_class.__name__, header_dict['Method:'],
 		dep, result.nobs, result.df_model, datetime.now(),
-		beta, result.pvalues,
+		terms,
 		result.llf, llnull,
 		getattr(result, 'df_resid', None), getattr(result, 'rsquared', None), getattr(result, 'fvalue', None),
 		exp
@@ -388,14 +482,14 @@ class PenalisedLogit(statsmodels.discrete.discrete_model.BinaryModel):
 				# Fit the model
 				model = ro.r('logistf(formula_, data=df)')
 				
-				beta = {t: Estimate(b, ci0, ci1) for t, b, ci0, ci1 in zip(model['terms'], model['coefficients'], model['ci.lower'], model['ci.upper'])}
+				# TODO: Handle categorical terms?
-				pvalues = {t: p for t, p in zip(model['terms'], model['prob'])}
+				terms = {t: SingleTerm(t, Estimate(b, ci0, ci1), p) for t, b, ci0, ci1, p in zip(model['terms'], model['coefficients'], model['ci.lower'], model['ci.upper'], model['prob'])}
 				
 				return RegressionResult(
 					model,
 					'Penalised Logistic Regression', 'Logit', 'Penalised ML',
 					self.endog_names, model['n'][0], model['df'][0], datetime.now(),
-					beta, pvalues,
+					terms,
 					model['loglik'][0], model['loglik'][1],
 					None, None, None,
 					None  # Set exp in regress()