Basic Data Analysis

Hey there! Curious about data's hidden secrets? Today, we dive into Basic Data Analysis—an essential step for data comprehension. We unearth patterns, and guide decision-making across various fields, be it business, science, or daily life, with a powerful tool—the pandas Python library. Let's embark on this journey!

Rising to the challenge of solving a data mystery, Basic Data Analysis serves as the groundwork. It encompasses understanding and decision-making—be it a business owner understanding customer behavior, a scientist analyzing research data, or a student making sense of study material. With pandas, this process becomes effortless.

Firstly, we employ value_counts(), a method that swiftly counts the frequency of DataFrame elements. Consider an imaginary dataset of pets.

import pandas as pd

# Creating DataFrame
data =  {'Name': ['Tommy', 'Rex', 'Bella', 'Charlie', 'Lucy', 'Cooper'],
         'Type': ['Dog', 'Dog', 'Cat', 'Cat', 'Dog', 'Bird']}
pets_df = pd.DataFrame(data)

Using the value_counts() function we can count count unique elements of a series (a dataframe column):

print(pets_df['Type'].value_counts())
# Output:
# Dog     3
# Cat     2
# Bird    1
# Name: Type, dtype: int64

With value_counts(), establishing frequency distribution in series becomes straightforward.

For summarizing data, groupby() and agg() prove useful! Now let’s add weight to the pets in our DataFrame to illustrate these methods:

import pandas as pd

# Creating DataFrame
data =  {'Name': ['Tommy', 'Rex', 'Bella', 'Charlie', 'Lucy', 'Cooper'],
         'Type': ['Dog', 'Dog', 'Cat', 'Cat', 'Dog', 'Bird'],
         'Weight': [12, 15, 8, 9, 14, 1]}
pets_df = pd.DataFrame(data)

Now group and calculate the mean of data based on pet type.

print(pets_df.groupby('Type').agg({'Weight': 'mean'}))

1. groupby('Type'): Splits the data into groups based on 'Type'.
2. .agg({'Weight': 'mean'}): Applies the 'mean' function to the 'Weight' column for each group.

The resulting DataFrame shows the average weight for each pet type:

• Bird: 1.0
• Cat: 8.5
• Dog: 13.67

Of course, calculating mean is not the only option. We can use functions like min, max, median, etc. We will talk more about using different aggregation functions in the next course.