Pass Data Between MATLAB and Python

When you return MATLAB^® data to Python^®, MATLAB Engine API for Python converts the data into the equivalent Python data type. MATLAB engine also converts incoming Python data into MATLAB data types.

Pass Data from MATLAB to Python

When you pass data from MATLAB to Python, either directly or as output from a MATLAB function in Python, MATLAB converts the data into the equivalent Python data types.

MATLAB Output Argument Type (scalar unless otherwise noted)	Resulting Python Data Type
Numeric array	`matlab` numeric array object See MATLAB Arrays as Python Variables.
`double` `single`	`float`
Complex (any numeric type)	`complex`
`int8`, `int16`, `int32`, `int64` `uint8`, `uint16`, `uint32`, `uint64`	`int`
`NaN`	`float('nan')`
`Inf`	`float('inf')`
`logical`	`bool`
`char` array (1-by-`N` or `N`-by-1)	`str`
`string`	`str`
`string` array (1-by-`N` or `N`-by-1)	`list` of `str`
`struct`	`dict`
cell array (1-by-`N` or `N`-by-1)	`list`
`datetime`	`datetime.datetime`
`duration`	`datetime.timedelta`
`datetime` array	`numpy.datetime64` array If the NumPy module is not available in the Python environment, MATLAB converts the `datetime` array to `matlab.object`.
`duration` array	`numpy.timedelta` array If the NumPy module is not available in the Python environment, MATLAB converts the `duration` array to `matlab.object`.
`table` `timetable`	`pandas.DataFrame` Only one level of nesting in tables is supported. If the Python Pandas module is not available in the Python environment, MATLAB converts the `table` or `timetable` to a `matlab.object`.
`dictionary`	`matlab.dictionary`.
MATLAB handle object (such as the `containers.Map` type)	`matlab.object` MATLAB returns a reference to a `matlab.object`, not the object itself. You cannot pass a `matlab.object` between MATLAB sessions.
MATLAB value object (such as the `categorical` type)	`matlab.object` You can pass a value object to a MATLAB function, but you cannot create or modify it.

Unsupported MATLAB Data Types

Along with the exceptions noted in the table, MATLAB does not convert these MATLAB data types to Python data types:

char array (M-by-N)
string array (M-by-N)
cell array (M-by-N)
Sparse array
struct array
Objects not produced by MATLAB (such as Java^® objects)
Function handle

Pass Data from Python to MATLAB

When you pass data from Python to MATLAB, either directly or as input arguments to a MATLAB function in Python, the MATLAB engine converts the data into the equivalent MATLAB data types.

Python Data Type	Resulting MATLAB Data Type (scalar unless otherwise noted)
`matlab` numeric array object	Numeric array See MATLAB Arrays as Python Variables.
Python objects that support the buffer protocol, such as `memoryview`, `array.array`, or NumPy `ndarray`	Numeric array
`float`	`double`
`complex`	Complex `double`
`int`	`int64`
`float('nan')`	`NaN`
`float('inf')`	`Inf`
`bool`	`logical`
`str`	`char`
`bytearray`	`uint8` array
`bytes`	`uint8` array
`list`	`cell` array
`set`	`cell` array
`tuple`	`cell` array
`dict`	`struct` `dict` keys must meet certain specifications. See Use Python Dictionaries in MATLAB.
`datetime.datetime` `numpy.datetime64` scalar	`datetime` See How MATLAB Handles Datetime and Duration Types in Python.
`datetime.timedelta` `numpy.timedelta64` scalar	`duration` See How MATLAB Handles Datetime and Duration Types in Python.
`numpy.datetime64` array	`datetime` array See How MATLAB Handles Datetime and Duration Types in Python.
`numpy.timedelta64` array	`duration` array See How MATLAB Handles Datetime and Duration Types in Python.
`pandas.DataFrame`	`table` Only one level of nesting in tables is supported. See Use MATLAB Tables and Timetables in Python.
`pandas.DataFrame` with `datetime` column	`timetable` Only one level of nesting in timetables is supported. See Use MATLAB Tables and Timetables in Python.
`matlab.dictionary`	`dictionary` `matlab.dictionary` keys and values must meet certain specifications. MATLAB converts the data in a `matlab.dictionary` object using the mappings in this table, with the exception that `str` data is converted to `string`. See Use Python Dictionaries in MATLAB.
Python objects other than `dict` that support the mapping protocol (such as `collections.OrderedDict`)	`dictionary`

Unsupported Python Data Types

Along with the exceptions noted in the table, MATLAB does not convert these Python data types to MATLAB data types:

Python class (module.type) objects
None object