7  pandas Fundamentals

7.1 Purpose

pandas is used to work with tabular data through DataFrame and Series objects.

7.2 Create a DataFrame

import pandas as pd

df = pd.DataFrame({
    "city": ["Puebla", "Oaxaca", "Mérida"],
    "year": [2024, 2024, 2025],
    "value": [18.2, 15.7, 21.4],
})

df

7.3 Select columns

selected = df[["city", "value"]]
selected

7.4 Filter rows

filtered = df.loc[df["value"] >= 18, ["city", "value"]]
filtered

7.5 Inspect data

df.head()
df.info()
df.describe()

7.6 Things to remember

• One bracket usually selects a Series.
• A list of column names selects a DataFrame.
• .loc selects by labels and conditions.
• Inspect types before performing calculations.