Sample() for random rows in Data Analysis Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the sample() function do in pandas?

The sample() function selects random rows from a DataFrame. It helps to get a random subset of data for analysis or testing.

beginner

How do you select 5 random rows from a DataFrame df?

Use df.sample(n=5). This picks 5 random rows without replacement by default.

beginner

What does the frac parameter do in sample()?

The frac parameter lets you select a fraction of rows randomly. For example, df.sample(frac=0.1) selects 10% of rows.

intermediate

How can you make the random selection reproducible using sample()?

Use the random_state parameter with a fixed number, like df.sample(n=3, random_state=42). This ensures the same rows are picked every time.

intermediate

What happens if you set replace=True in sample()?

Setting replace=True allows sampling with replacement. This means the same row can be picked multiple times.

Which pandas function is used to select random rows from a DataFrame?

A random()

B sample()

C select()

D shuffle()

The sample() function is designed to select random rows from a DataFrame.

How do you select 20% of rows randomly from a DataFrame df?

A df.sample(size=0.2)

B df.sample(n=20)

C df.sample(percent=20)

D df.sample(frac=0.2)

Use the frac parameter with a decimal fraction like 0.2 to select 20% of rows.

What does setting random_state in sample() do?

A Makes the random selection reproducible

B Sorts the sampled rows

C Samples rows with replacement

D Changes the number of rows sampled

Setting random_state fixes the random seed so the same rows are selected every time.

If you want to allow the same row to be picked multiple times, which parameter should you use?

A replace=True

B random_state=True

C replace=False

D frac=True

Setting replace=True allows sampling with replacement, so rows can repeat.

What is the default behavior of sample() regarding replacement?

A Sampling with replacement

B Depends on the DataFrame size

C Sampling without replacement

D Depends on the random_state

By default, sample() samples without replacement, so rows are unique in the sample.

Explain how to use pandas sample() to get a random subset of rows from a DataFrame.

Think about how to pick random rows and keep results consistent.

Describe the effect of the replace parameter in the sample() function.

Consider if the same row can appear multiple times or not.