Masked arrays#

Masked arrays

#

Masked arrays are arrays that may have missing or invalid entries. The

numpy.ma

module provides a nearly work-alike replacement for numpy that supports data arrays with masks.

The numpy.ma module

Rationale

What is a masked array?

The numpy.ma module

Using numpy.ma

Constructing masked arrays

Accessing the data

Accessing the mask

Accessing only the valid entries

Modifying the mask

Indexing and slicing

Operations on masked arrays

Examples

Data with a given value representing missing data

Filling in the missing data

Numerical operations

Ignoring extreme values

Constants of the numpy.ma module

masked

nomask

masked_print_option

The MaskedArray class

MaskedArray

Attributes and properties of masked arrays

MaskedArray methods

Conversion

Shape manipulation

Item selection and manipulation

Pickling and copy

Calculations

Arithmetic and comparison operations

Representation

Special methods

Specific methods

Masked array operations

Constants

Creation

Inspecting the array

Manipulating a MaskedArray

Operations on masks

Conversion operations

Masked arrays arithmetic