Summary  
Using pandas DataFrame methods to inspect dataset metadata—retrieving and printing the number of rows and columns, column names, and data types with info() and len().  

General domain of usage  
Data analysis

In `pandas`, there's a handy method named `info()` that provides basic information about a dataset.

import pandas as pd
# It's a dataframe
df = pd.read_csv('https://codefinity-content-media.s3.eu-west-1.amazonaws.com/a43d24b6-df61-4e11-9c90-5b36552b3437/example.csv')
info = df.info()
print(info)

This method displays the number of rows and columns in the DataFrame, as well as each column's name and data type. For instance, `df` contains **20** rows and **5** columns.

To determine the length of a `DataFrame`, use the `len()` function, as shown in the example below:

```python
length = len(df)
```

import unittest
import importlib
import pandas as pd
from io import StringIO
import re


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)


class TestUserCode(unittest.TestCase):

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

    def test_info_method_is_used(self):
        with open('user_code.py', 'r') as file:
            user_code_source = file.read()

        _dynamic_test(
            self,
            re.search(r'\.info\s*\(', user_code_source),
            "The `info()` method is used.",
            "Expected the `info()` method to be used."
        )


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

test_main.py

Build practical data manipulation skills using pandas. Learn to work with Series and DataFrames, read and explore datasets, select and filter data, perform aggregations, reshape tables, combine multiple DataFrames, and prepare data for analysis.

Exploring the Dataset

Ratkaisu