For at implementere logistisk regression i Python anvendes `LogisticRegression`-klassen:

Du kan indtil videre benytte standardparametrene. Oprettelse og tilpasning af modellen kan udføres på én linje:

```python
logistic_regression = LogisticRegression().fit(X_train, y_train)
```

Datasættet til dette kapitel stammer fra en **portugisisk bankinstitution** og indeholder oplysninger fra markedsføringskampagner udført via telefonopkald. Målet er at forudsige, om en kunde vil **tegne en tidsindskudskonto**, baseret på personlige, økonomiske og kontaktrelaterede oplysninger samt resultater fra tidligere markedsføringsinteraktioner.
  
Dataene er allerede forbehandlede og klar til at blive brugt i modellen.

import unittest
import importlib
import numpy as np


def _dynamic_test(test_case, condition, success_message, failure_message):
    if condition:
        test_case._testMethodName = success_message
        test_case.assertTrue(True, success_message)
    else:
        test_case._testMethodName = failure_message
        test_case.fail(failure_message)


def get_first_differing_index(expected_array, actual_array):
    for i, (val_1, val_2) in enumerate(zip(expected_array, actual_array)):
        if not np.array_equal(val_1, val_2):
            return i, expected_array[i], actual_array[i]

    if len(expected_array) > len(actual_array):
        return len(actual_array), expected_array[len(actual_array)], None
    else:
        return len(expected_array), None, actual_array[len(expected_array)]


class TestUserCode(unittest.TestCase):

    def test_X_train_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, 'X_train'),
            "The `X_train` variable is declared.",
            "Expected `X_train` to be declared."
        )

    def test_X_test_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, 'X_test'),
            "The `X_test` variable is declared.",
            "Expected `X_test` to be declared."
        )

    def test_y_train_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, 'y_train'),
            "The `y_train` variable is declared.",
            "Expected `y_train` to be declared."
        )

    def test_y_test_is_declared(self):
        import user_code
        _dynamic_test(
            self,
            hasattr(user_code, 'y_test'),
            "The `y_test` variable is declared.",
            "Expected `y_test` to be declared."
        )

    def test_X_train_is_correct(self):
        import user_code
        import pandas as pd
        from sklearn.model_selection import train_test_split

        df = pd.read_csv(
            'https://codefinity-content-media.s3.eu-west-1.amazonaws.com/b71ff7ac-3932-41d2-a4d8-060e24b00129/marketing_bank.csv')
        X = df.drop('deposit', axis=1).values
        y = df['deposit'].values
        expected_value, _, _, _ = train_test_split(X, y, test_size=0.2, random_state=42)

        variable = 'X_train'
        actual_value = getattr(user_code, variable, None)
        condition = False
        if actual_value is None:
            failure_message = f"The `{variable}` variable is not declared."
        elif not isinstance(actual_value, np.ndarray):
            failure_message = f"`{variable}` is not a `numpy.ndarray`."
        elif actual_value.size == 0:
            failure_message = f"`{variable}` is empty."
        elif np.array_equal(actual_value, expected_value):
            condition = True
            failure_message = None
        else:
            if actual_value.shape != expected_value.shape:
                failure_message = f"The shape of `{variable}` is incorrect."
            else:
                for i in range(actual_value.shape[0]):
                    if np.array_equal(actual_value[i], expected_value[i]):
                        continue
                    idx, expected_element, actual_element = get_first_differing_index(expected_value[i], actual_value[i])
                    failure_message = f"Expected `{variable}` to contain `{expected_element}` at index [{i}, {idx}], but got `{actual_element}`."
                    break

        _dynamic_test(
            self,
            condition,
            f"`{variable}` contains the correct data.",
            failure_message
        )

    def test_X_test_is_correct(self):
        import user_code
        import pandas as pd
        from sklearn.model_selection import train_test_split

        df = pd.read_csv(
            'https://codefinity-content-media.s3.eu-west-1.amazonaws.com/b71ff7ac-3932-41d2-a4d8-060e24b00129/marketing_bank.csv')
        X = df.drop('deposit', axis=1).values
        y = df['deposit'].values
        _, expected_value, _, _ = train_test_split(X, y, test_size=0.2, random_state=42)

        variable = 'X_test'
        actual_value = getattr(user_code, variable, None)
        condition = False
        if actual_value is None:
            failure_message = f"The `{variable}` variable is not declared."
        elif not isinstance(actual_value, np.ndarray):
            failure_message = f"`{variable}` is not a `numpy.ndarray`."
        elif actual_value.size == 0:
            failure_message = f"`{variable}` is empty."
        elif np.array_equal(actual_value, expected_value):
            condition = True
            failure_message = None
        else:
            if actual_value.shape != expected_value.shape:
                failure_message = f"The shape of `{variable}` is incorrect."
            else:
                for i in range(actual_value.shape[0]):
                    if np.array_equal(actual_value[i], expected_value[i]):
                        continue
                    idx, expected_element, actual_element = get_first_differing_index(expected_value[i],
                                                                                      actual_value[i])
                    failure_message = f"Expected `{variable}` to contain `{expected_element}` at index [{i}, {idx}], but got `{actual_element}`."
                    break

        _dynamic_test(
            self,
            condition,
            f"`{variable}` contains the correct data.",
            failure_message
        )

    def test_y_train_is_correct(self):
        import user_code
        import pandas as pd
        from sklearn.model_selection import train_test_split

        df = pd.read_csv(
            'https://codefinity-content-media.s3.eu-west-1.amazonaws.com/b71ff7ac-3932-41d2-a4d8-060e24b00129/marketing_bank.csv')
        X = df.drop('deposit', axis=1).values
        y = df['deposit'].values
        _, _, expected_value, _ = train_test_split(X, y, test_size=0.2, random_state=42)

        variable = 'y_train'
        actual_value = getattr(user_code, variable, None)
        condition = False
        if actual_value is None:
            failure_message = f"The `{variable}` variable is not declared."
        elif not isinstance(actual_value, np.ndarray):
            failure_message = f"`{variable}` is not a `numpy.ndarray`."
        elif actual_value.size == 0:
            failure_message = f"`{variable}` is empty."
        elif np.array_equal(actual_value, expected_value):
            condition = True
            failure_message = None
        else:
            idx, expected_element, actual_element = get_first_differing_index(expected_value, actual_value)
            failure_message = f"Expected `{variable}` to contain `{expected_element}` at index {idx}, but got `{actual_element}`."

        _dynamic_test(
            self,
            condition,
            f"`{variable}` contains the correct data.",
            failure_message
        )

    def test_y_test_is_correct(self):
        import user_code
        import pandas as pd
        from sklearn.model_selection import train_test_split

        df = pd.read_csv(
            'https://codefinity-content-media.s3.eu-west-1.amazonaws.com/b71ff7ac-3932-41d2-a4d8-060e24b00129/marketing_bank.csv')
        X = df.drop('deposit', axis=1).values
        y = df['deposit'].values
        _, _, _, expected_value = train_test_split(X, y, test_size=0.2, random_state=42)

        variable = 'y_test'
        actual_value = getattr(user_code, variable, None)
        condition = False
        if actual_value is None:
            failure_message = f"The `{variable}` variable is not declared."
        elif not isinstance(actual_value, np.ndarray):
            failure_message = f"`{variable}` is not a `numpy.ndarray`."
        elif actual_value.size == 0:
            failure_message = f"`{variable}` is empty."
        elif np.array_equal(actual_value, expected_value):
            condition = True
            failure_message = None
        else:
            idx, expected_element, actual_element = get_first_differing_index(expected_value, actual_value)
            failure_message = f"Expected `{variable}` to contain `{expected_element}` at index {idx}, but got `{actual_element}`."

        _dynamic_test(
            self,
            condition,
            f"`{variable}` contains the correct data.",
            failure_message
        )

    def test_lr_is_declared(self):
        import user_code

        variable = 'lr'
        _dynamic_test(
            self,
            hasattr(user_code, variable),
            f"The `{variable}` variable is declared.",
            f"Expected `{variable}` to be declared."
        )

    def test_lr_is_correct(self):
        import user_code
        import pandas as pd
        from sklearn.linear_model import LogisticRegression
        from sklearn.model_selection import train_test_split

        df = pd.read_csv(
            'https://codefinity-content-media.s3.eu-west-1.amazonaws.com/b71ff7ac-3932-41d2-a4d8-060e24b00129/marketing_bank.csv')
        X = df.drop('deposit', axis=1)
        y = df['deposit']
        X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)

        expected_value = LogisticRegression().fit(X_train, y_train)

        variable = 'lr'
        actual_value = getattr(user_code, variable, None)
        condition = False
        if actual_value is None:
            failure_message = f"The `{variable}` variable is not declared."
        elif isinstance(actual_value, LogisticRegression):
            if np.array_equal(actual_value.coef_, expected_value.coef_):
                condition = True
                failure_message = None
            else:
                idx, expected_element, actual_element = get_first_differing_index(expected_value.coef_[0], actual_value.coef_[0])
                failure_message = f"Expected the coefficients of the model to contain `{expected_element}` at index {idx}, but got `{actual_element}`."
        else:
            failure_message = f"`{variable}` is not a `LogisticRegression`."

        _dynamic_test(
            self,
            condition,
            f"`{variable}` is a correctly fitted `LogisticRegression`.",
            failure_message
        )

    def test_test_accuracy_declared(self):
        import user_code

        variable = 'test_accuracy'
        _dynamic_test(
            self,
            hasattr(user_code, variable),
            f"The `{variable}` variable is declared.",
            f"Expected `{variable}` to be declared."
        )

    def test_test_accuracy_is_correct(self):
        import user_code
        expected_value = 0.8083296014330497

        variable = 'test_accuracy'
        actual_value = getattr(user_code, variable, None)
        if actual_value is None:
            condition = False
            failure_message = f"The `{variable}` variable is not declared."
        elif isinstance(actual_value, float):
            condition = actual_value == expected_value
            failure_message = f"Expected `{variable}` to be `{expected_value}`, but got `{actual_value}`."
        else:
            condition = False
            failure_message = f"`{variable}` is not a `float`."

        _dynamic_test(
            self,
            condition,
            f"`{variable}` is correct.",
            failure_message
        )


if __name__ == '__main__':
    unittest.main()

test_main.py

Behersk de centrale klassifikationsalgoritmer, der driver moderne maskinlæring. Udforsk hvordan modeller som k-NN, logistisk regression, beslutningstræer og random forests foretager forudsigelser, evaluerer deres nøjagtighed, og forstå hvornår hver model bør anvendes. Opbyg færdigheder til at sammenligne modeller og vælge den bedste til dine data.

Opdag, hvordan k-nærmeste naboer-algoritmen foretager forudsigelser baseret på lighed. Lær at håndtere flere egenskaber, justere parametre og anvende krydsvalidering for at forbedre nøjagtigheden.

Forstå, hvordan logistisk regression modellerer sandsynligheder og klassificerer udfald. Øv implementering, fortolkning af beslutningsgrænser og anvendelse af regularisering for at forhindre overfitting.

Lær, hvordan beslutningstræer opdeler data i meningsfulde grupper baseret på featureværdier. Udforsk, hvordan parametre som trædybde og minimum antal prøver per blad påvirker modellens ydeevne og generalisering.

Undersøg, hvordan random forests kombinerer flere beslutningstræer for at forbedre nøjagtighed og robusthed. Forstå betydningen af tilfældighed og anvend denne ensemble-metode på virkelige data.

Evaluering af modeller ved hjælp af metrikker såsom nøjagtighed, præcision, recall og F1-score. Lær at fortolke forvekslingsmatrixer og sammenligne flere klassifikatorer for at identificere den bedst præsterende model.

Udfordring: Implementering af Logistisk Regression

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Awesome!

Udfordring: Implementering af Logistisk Regression

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