Record arrays in NumPy - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a record array in NumPy?

A record array is a special type of NumPy array that allows you to access fields by attribute name, similar to columns in a table. It stores heterogeneous data types in one array.

beginner

How do you create a record array from a structured array in NumPy?

You can create a record array by calling the .view(np.recarray) method on a structured array. This lets you access fields as attributes.

beginner

How do you access a field named 'age' in a NumPy record array?

You can access it using dot notation like array.age or by dictionary-style indexing like array['age'].

intermediate

What is the difference between a structured array and a record array in NumPy?

A structured array stores data with named fields but you access fields using dictionary-style indexing. A record array allows access to fields using attribute (dot) notation.

beginner

Why might you use a record array instead of a regular NumPy array?

Record arrays let you work with mixed data types and access fields by name easily, which is helpful when handling tabular data with different types in each column.

How do you create a record array from a structured array named 'data'?

A data.view(np.recarray)

B np.array(data, dtype='recarray')

C np.recarray(data)

D data.to_recarray()

You create a record array by calling the .view(np.recarray) method on the structured array.

Which syntax accesses the 'name' field in a record array 'rec'?

A rec['name']

B Both A and B

C rec.name()

D rec.name

In record arrays, you can access fields either by dictionary-style indexing or dot notation.

What kind of data can a record array hold?

A Only numbers

B Only strings

C Only booleans

D Mixed data types in different fields

Record arrays can hold mixed data types in different fields, like numbers, strings, and more.

What is the main advantage of using a record array over a structured array?

A Faster computation

B Uses less memory

C Access fields with dot notation

D Supports only numeric data

Record arrays allow accessing fields using dot notation, which is more convenient.

Which NumPy module provides the recarray class?

A numpy.rec

B numpy.recarray

C numpy.core.records

D cer.ypmun

The recarray class is available in the numpy.rec module.

Explain what a record array is and how it differs from a regular NumPy array.

Think about how you access data fields and the types of data stored.

Describe how to create a record array from a structured array and how to access its fields.

Focus on the method to convert and the two ways to get field data.