Add example app

app.py

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+import streamlit as st
+import pandas as pd
+import numpy as np
+from sklearn.model_selection import train_test_split
+from sklearn.ensemble import RandomForestRegressor
+from sklearn.metrics import mean_squared_error, r2_score
+import altair as alt
+import time
+import zipfile
+
+# Page title
+st.set_page_config(page_title='ML Model Building', page_icon='🤖')
+st.title('🤖 ML Model Building')
+
+with st.expander('About this app'):
+  st.markdown('**What can this app do?**')
+  st.info('This app allow users to build a machine learning (ML) model in an end-to-end workflow. Particularly, this encompasses data upload, data pre-processing, ML model building and post-model analysis.')
+
+  st.markdown('**How to use the app?**')
+  st.warning('To engage with the app, go to the sidebar and 1. Select a data set and 2. Adjust the model parameters by adjusting the various slider widgets. As a result, this would initiate the ML model building process, display the model results as well as allowing users to download the generated models and accompanying data.')
+
+  st.markdown('**Under the hood**')
+  st.markdown('Data sets:')
+  st.code('''- Drug solubility data set
+  ''', language='markdown')
+  
+  st.markdown('Libraries used:')
+  st.code('''- Pandas for data wrangling
+- Scikit-learn for building a machine learning model
+- Altair for chart creation
+- Streamlit for user interface
+  ''', language='markdown')
+
+
+# Sidebar for accepting input parameters
+with st.sidebar:
+    # Load data
+    st.header('1.1. Input data')
+
+    st.markdown('**1. Use custom data**')
+    uploaded_file = st.file_uploader("Upload a CSV file", type=["csv"])
+    if uploaded_file is not None:
+        df = pd.read_csv(uploaded_file, index_col=False)
+      
+    # Download example data
+    @st.cache_data
+    def convert_df(input_df):
+        return input_df.to_csv(index=False).encode('utf-8')
+    example_csv = pd.read_csv('https://raw.githubusercontent.com/dataprofessor/data/master/delaney_solubility_with_descriptors.csv')
+    csv = convert_df(example_csv)
+    st.download_button(
+        label="Download example CSV",
+        data=csv,
+        file_name='delaney_solubility_with_descriptors.csv',
+        mime='text/csv',
+    )
+
+    # Select example data
+    st.markdown('**1.2. Use example data**')
+    example_data = st.toggle('Load example data')
+    if example_data:
+        df = pd.read_csv('https://raw.githubusercontent.com/dataprofessor/data/master/delaney_solubility_with_descriptors.csv')
+
+    st.header('2. Set Parameters')
+    parameter_split_size = st.slider('Data split ratio (% for Training Set)', 10, 90, 80, 5)
+
+    st.subheader('2.1. Learning Parameters')
+    with st.expander('See parameters'):
+        parameter_n_estimators = st.slider('Number of estimators (n_estimators)', 0, 1000, 100, 100)
+        parameter_max_features = st.select_slider('Max features (max_features)', options=['all', 'sqrt', 'log2'])
+        parameter_min_samples_split = st.slider('Minimum number of samples required to split an internal node (min_samples_split)', 2, 10, 2, 1)
+        parameter_min_samples_leaf = st.slider('Minimum number of samples required to be at a leaf node (min_samples_leaf)', 1, 10, 2, 1)
+
+    st.subheader('2.2. General Parameters')
+    with st.expander('See parameters', expanded=False):
+        parameter_random_state = st.slider('Seed number (random_state)', 0, 1000, 42, 1)
+        parameter_criterion = st.select_slider('Performance measure (criterion)', options=['squared_error', 'absolute_error', 'friedman_mse'])
+        parameter_bootstrap = st.select_slider('Bootstrap samples when building trees (bootstrap)', options=[True, False])
+        parameter_oob_score = st.select_slider('Whether to use out-of-bag samples to estimate the R^2 on unseen data (oob_score)', options=[False, True])
+
+    sleep_time = st.slider('Sleep time', 0, 3, 0)
+
+# Initiate the model building process
+if uploaded_file or example_data: 
+    with st.status("Running ...", expanded=True) as status:
+    
+        st.write("Loading data ...")
+        time.sleep(sleep_time)
+
+        st.write("Preparing data ...")
+        time.sleep(sleep_time)
+        X = df.iloc[:,:-1]
+        y = df.iloc[:,-1]
+            
+        st.write("Splitting data ...")
+        time.sleep(sleep_time)
+        X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=(100-parameter_split_size)/100, random_state=parameter_random_state)
+    
+        st.write("Model training ...")
+        time.sleep(sleep_time)
+
+        if parameter_max_features == 'all':
+            parameter_max_features = None
+            parameter_max_features_metric = X.shape[1]
+        
+        rf = RandomForestRegressor(
+                n_estimators=parameter_n_estimators,
+                max_features=parameter_max_features,
+                min_samples_split=parameter_min_samples_split,
+                min_samples_leaf=parameter_min_samples_leaf,
+                random_state=parameter_random_state,
+                criterion=parameter_criterion,
+                bootstrap=parameter_bootstrap,
+                oob_score=parameter_oob_score)
+        rf.fit(X_train, y_train)
+        
+        st.write("Applying model to make predictions ...")
+        time.sleep(sleep_time)
+        y_train_pred = rf.predict(X_train)
+        y_test_pred = rf.predict(X_test)
+            
+        st.write("Evaluating performance metrics ...")
+        time.sleep(sleep_time)
+        train_mse = mean_squared_error(y_train, y_train_pred)
+        train_r2 = r2_score(y_train, y_train_pred)
+        test_mse = mean_squared_error(y_test, y_test_pred)
+        test_r2 = r2_score(y_test, y_test_pred)
+        
+        st.write("Displaying performance metrics ...")
+        time.sleep(sleep_time)
+        parameter_criterion_string = ' '.join([x.capitalize() for x in parameter_criterion.split('_')])
+        #if 'Mse' in parameter_criterion_string:
+        #    parameter_criterion_string = parameter_criterion_string.replace('Mse', 'MSE')
+        rf_results = pd.DataFrame(['Random forest', train_mse, train_r2, test_mse, test_r2]).transpose()
+        rf_results.columns = ['Method', f'Training {parameter_criterion_string}', 'Training R2', f'Test {parameter_criterion_string}', 'Test R2']
+        # Convert objects to numerics
+        for col in rf_results.columns:
+            rf_results[col] = pd.to_numeric(rf_results[col], errors='ignore')
+        # Round to 3 digits
+        rf_results = rf_results.round(3)
+        
+    status.update(label="Status", state="complete", expanded=False)
+
+    # Display data info
+    st.header('Input data', divider='rainbow')
+    col = st.columns(4)
+    col[0].metric(label="No. of samples", value=X.shape[0], delta="")
+    col[1].metric(label="No. of X variables", value=X.shape[1], delta="")
+    col[2].metric(label="No. of Training samples", value=X_train.shape[0], delta="")
+    col[3].metric(label="No. of Test samples", value=X_test.shape[0], delta="")
+    
+    with st.expander('Initial dataset', expanded=True):
+        st.dataframe(df, height=210, use_container_width=True)
+    with st.expander('Train split', expanded=False):
+        train_col = st.columns((3,1))
+        with train_col[0]:
+            st.markdown('**X**')
+            st.dataframe(X_train, height=210, hide_index=True, use_container_width=True)
+        with train_col[1]:
+            st.markdown('**y**')
+            st.dataframe(y_train, height=210, hide_index=True, use_container_width=True)
+    with st.expander('Test split', expanded=False):
+        test_col = st.columns((3,1))
+        with test_col[0]:
+            st.markdown('**X**')
+            st.dataframe(X_test, height=210, hide_index=True, use_container_width=True)
+        with test_col[1]:
+            st.markdown('**y**')
+            st.dataframe(y_test, height=210, hide_index=True, use_container_width=True)
+
+    # Zip dataset files
+    df.to_csv('dataset.csv', index=False)
+    X_train.to_csv('X_train.csv', index=False)
+    y_train.to_csv('y_train.csv', index=False)
+    X_test.to_csv('X_test.csv', index=False)
+    y_test.to_csv('y_test.csv', index=False)
+    
+    list_files = ['dataset.csv', 'X_train.csv', 'y_train.csv', 'X_test.csv', 'y_test.csv']
+    with zipfile.ZipFile('dataset.zip', 'w') as zipF:
+        for file in list_files:
+            zipF.write(file, compress_type=zipfile.ZIP_DEFLATED)
+
+    with open('dataset.zip', 'rb') as datazip:
+        btn = st.download_button(
+                label='Download ZIP',
+                data=datazip,
+                file_name="dataset.zip",
+                mime="application/octet-stream"
+                )
+    
+    # Display model parameters
+    st.header('Model parameters', divider='rainbow')
+    parameters_col = st.columns(3)
+    parameters_col[0].metric(label="Data split ratio (% for Training Set)", value=parameter_split_size, delta="")
+    parameters_col[1].metric(label="Number of estimators (n_estimators)", value=parameter_n_estimators, delta="")
+    parameters_col[2].metric(label="Max features (max_features)", value=parameter_max_features_metric, delta="")
+    
+    # Display feature importance plot
+    importances = rf.feature_importances_
+    feature_names = list(X.columns)
+    forest_importances = pd.Series(importances, index=feature_names)
+    df_importance = forest_importances.reset_index().rename(columns={'index': 'feature', 0: 'value'})
+    
+    bars = alt.Chart(df_importance).mark_bar(size=40).encode(
+             x='value:Q',
+             y=alt.Y('feature:N', sort='-x')
+           ).properties(height=250)
+
+    performance_col = st.columns((2, 0.2, 3))
+    with performance_col[0]:
+        st.header('Model performance', divider='rainbow')
+        st.dataframe(rf_results.T.reset_index().rename(columns={'index': 'Parameter', 0: 'Value'}))
+    with performance_col[2]:
+        st.header('Feature importance', divider='rainbow')
+        st.altair_chart(bars, theme='streamlit', use_container_width=True)
+
+    # Prediction results
+    st.header('Prediction results', divider='rainbow')
+    s_y_train = pd.Series(y_train, name='actual').reset_index(drop=True)
+    s_y_train_pred = pd.Series(y_train_pred, name='predicted').reset_index(drop=True)
+    df_train = pd.DataFrame(data=[s_y_train, s_y_train_pred], index=None).T
+    df_train['class'] = 'train'
+        
+    s_y_test = pd.Series(y_test, name='actual').reset_index(drop=True)
+    s_y_test_pred = pd.Series(y_test_pred, name='predicted').reset_index(drop=True)
+    df_test = pd.DataFrame(data=[s_y_test, s_y_test_pred], index=None).T
+    df_test['class'] = 'test'
+    
+    df_prediction = pd.concat([df_train, df_test], axis=0)
+    
+    prediction_col = st.columns((2, 0.2, 3))
+    
+    # Display dataframe
+    with prediction_col[0]:
+        st.dataframe(df_prediction, height=320, use_container_width=True)
+
+    # Display scatter plot of actual vs predicted values
+    with prediction_col[2]:
+        scatter = alt.Chart(df_prediction).mark_circle(size=60).encode(
+                        x='actual',
+                        y='predicted',
+                        color='class'
+                  )
+        st.altair_chart(scatter, theme='streamlit', use_container_width=True)
+
+    
+# Ask for CSV upload if none is detected
+else:
+    st.warning('👈 Upload a CSV file or click *"Load example data"* to get started!')

requirements.txt

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+streamlit==1.29.0
+pandas>=1.3.0
+scikit-learn
+altair>=4.0