Combining conditions in NumPy - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does combining conditions mean in numpy?

It means using multiple conditions together to filter or select data, like checking if values meet several rules at once.

beginner

How do you combine conditions with AND in numpy?

Use the & operator between conditions, and put each condition in parentheses. For example: (arr > 5) & (arr < 10).

beginner

How do you combine conditions with OR in numpy?

Use the | operator between conditions, with each condition in parentheses. For example: (arr < 3) | (arr > 7).

intermediate

Why must conditions be in parentheses when combining in numpy?

Because & and | have lower precedence than comparison operators, parentheses make sure each condition is evaluated first before combining.

intermediate

What happens if you forget to use parentheses when combining conditions in numpy?

You get an error or wrong results because numpy tries to combine the whole expression incorrectly.

Which operator is used for AND when combining conditions in numpy?

A and

B &&

C &

D |

In numpy, & is used for element-wise AND between conditions.

How should you write a condition to select values greater than 10 and less than 20 in numpy?

A arr > 10 and arr < 20

B arr > 10 & arr < 20

C arr > (10 & arr) < 20

D (arr > 10) & (arr < 20)

Each condition must be in parentheses when combined with &.

What does the | operator do when combining conditions in numpy?

A OR

B XOR

C NOT

D AND

| means OR, selecting elements that meet at least one condition.

What error might you get if you forget parentheses in combined numpy conditions?

A ValueError

B TypeError

C SyntaxError

D No error, works fine

Without parentheses, numpy raises a ValueError due to wrong operator precedence.

Which is the correct way to select values less than 5 or greater than 15 in numpy?

A arr < (5 | arr) > 15

B (arr < 5) | (arr > 15)

C arr < 5 | arr > 15

D (arr < 5) & (arr > 15)

Use | for OR and parentheses around each condition.

Explain how to combine multiple conditions in numpy to filter an array.

Think about how to join conditions like 'greater than' and 'less than' checks.

What are common mistakes when combining conditions in numpy and how to avoid them?

Focus on operator precedence and syntax rules.