NumPy Logic functions: isfortran() function

numpy.isfortran() function

The isfortran() function is used to returns True if the array is Fortran contiguous but not C contiguous.

This function is obsolete and, because of changes due to relaxed stride checking,
its return value for the same array may differ for versions of NumPy >= 1.10.0 and previous versions.
If you only want to check if an array is Fortran contiguous use a.flags.f_contiguous instead.

Syntax:

numpy.isfortran(a)

Version: 1.15.0

Parameter:

Returns:
all : ndarray, bool - A new boolean or array is returned unless out is specified, in which case a reference to out is returned.

NumPy.isfortran() method Example:

np.array allows to specify whether the array is written in C-contiguous order (last index varies the fastest),
or FORTRAN-contiguous order in memory (first index varies the fastest).

>>> import numpy as np
>>> x = np.array([[1, 3, 5], [2, 4, 6]], order='C')
>>> x

Output:

array([[1, 3, 5],
       [2, 4, 6]])

>>> import numpy as np
>>> x = np.array([[1, 3, 5], [2, 4, 6]], order='C')
>>> np.isfortran(x)

Output:

False

>>> import numpy as np
>>> y = np.array([[1, 3, 5], [2, 4, 6]], order='F') # FORTRAN = 'F'
>>> y

Output:

array([[1, 3, 5],
       [2, 4, 6]])

>>> import numpy as np
>>> y = np.array([[1, 2, 3], [4, 5, 6]], order='F') # FORTRAN = 'F'
>>> np.isfortran(y)

Output:

True

The transpose of a C-ordered array is a FORTRAN-ordered array.

>>> import numpy as np
>>> x = np.array([[1, 2, 3], [4, 5, 6]], order='C')
>>> x

Output:

array([[1, 2, 3],
       [4, 5, 6]])

The transpose of a C-ordered array is a FORTRAN-ordered array.

>>> import numpy as np
>>> x = np.array([[1, 3, 5], [2, 4, 6]], order='C')
>>> np.isfortran(x)

Output:

False

>>> import numpy as np
>>> x = np.array([[1, 3, 5], [2, 4, 6]], order='C')
>>> y = x.T
>>> y

Output:

array([[1, 2],
       [3, 4],
       [5, 6]])

>>> import numpy as np
>>> x = np.array([[1, 3, 5], [2, 4, 6]], order='C')
>>> y = x.T
>>> np.isfortran(y)

Output:

True

C-ordered arrays evaluate as False even if they are also FORTRAN-ordered.

>>> import numpy as np
>>> np.isfortran(np.array([1, 5], order='F')) # FORTRAN = 'F'

Output:

False

Python - NumPy Code Editor:

Previous: iscomplexobj() function
Next: isreal() function