[practice]Pandas Fundamentals
Filtering Rows
# theory
boolean indexing
The most powerful way to filter data. Create a True/False mask and use it to select rows:
# Create boolean mask
mask = df["age"] > 25
print(mask) # Series of True/False
# Apply mask to filter
older_people = df[mask]
# Or in one line:
older_people = df[df["age"] > 25]operators
df[df["price"] > 50] # Greater than
df[df["price"] >= 50] # Greater than or equal
df[df["price"] == 50] # Equal
df[df["price"] != 50] # Not equal
df[df["name"] == "Alice"] # String equalitycombining conditions
Use & (and) and | (or). Wrap each condition in parentheses!
# AND - both must be true
df[(df["age"] > 25) & (df["city"] == "NYC")]
# OR - either can be true
df[(df["age"] < 20) | (df["age"] > 60)]useful methods
# isin() - check membership in a list
df[df["city"].isin(["NYC", "LA", "Chicago"])]
# between() - range check (inclusive)
df[df["age"].between(25, 35)]
# String methods
df[df["name"].str.startswith("A")]
df[df["name"].str.contains("ali", case=False)]# examples [3]
# example 01 · basic filtering
Filter rows based on a condition
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# example 02 · multiple conditions
Combine conditions with & (and) and | (or)
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# example 03 · using isin and between
Convenient methods for common patterns
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# challenges [2]
# challenge 01/02todo
Filter sales to show only products with price > 20. Print the result.
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# challenge 02/02todo
Filter students who have grade 'A' OR grade 'B'. Print the result.
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# project
# project-challenge
thread: SF Permits Analysis · reward: 50 xp
# brief
The city wants to see only permits that are currently active. Filter to show permits that are either 'issued' or 'complete' status.
# task
Filter Active Permits
# your code
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