# Numpy MaskedArray.ravel() function | Python

• Last Updated : 03 Oct, 2019

`numpy.MaskedArray.ravel()` function is used to return a 1D version of self mask array, as a view.

Syntax : `numpy.ma.ravel(self, order='C')`

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Parameters:
order : [‘C’, ‘F’, ‘A’, ‘K’, optional] By default, ‘C’ index order is used.
–> The elements of a are read using this index order.
–> ‘C’ means to index the elements in C-like order, with the last axis index changing fastest, back to the first axis index changing slowest.
–> ‘F’ means to index the elements in Fortran-like index order, with the first index changing fastest, and the last index changing slowest.
–> ‘A’ means to read the elements in Fortran-like index order if m is Fortran contiguous in memory, C-like order otherwise.
–> ‘K’ means to read the elements in the order they occur in memory, except for reversing the data when strides are negative.

Code #1 :

 `# Python program explaining``# numpy.MaskedArray.ravel() method ``   ` `# importing numpy as geek  ``# and numpy.ma module as ma ``import` `numpy as geek ``import` `numpy.ma as ma ``   ` `# creating input array  ``in_arr ``=` `geek.array([[``1``, ``2``], [ ``3``, ``-``1``]]) ``print` `(``"Input array : "``, in_arr) ``   ` `# Now we are creating a masked array. ``# by making two entry as invalid.  ``mask_arr ``=` `ma.masked_array(in_arr, mask ``=``[[``0``, ``1``], [ ``1``, ``0``]]) ``print` `(``"Masked array : "``, mask_arr) ``   ` `# applying MaskedArray.ravel methods to mask array ``out_arr ``=` `mask_arr.ravel() ``print` `(``"1D view of masked array : "``, out_arr) `
Output:
```Input array :  [[ 1  2]
[ 3 -1]]
[-- -1]]
1D view of masked array :  [1 -- -- -1]
```

Code #2 :

 `# Python program explaining``# numpy.MaskedArray.ravel() method ``   ` `# importing numpy as geek  ``# and numpy.ma module as ma ``import` `numpy as geek ``import` `numpy.ma as ma ``   ` `# creating input array ``in_arr ``=` `geek.array([[[ ``2e8``, ``3e``-``5``]], [[ ``-``45.0``, ``2e5``]]])``print` `(``"Input array : "``, in_arr)``   ` `# Now we are creating a masked array. ``# by making one entry as invalid.  ``mask_arr ``=` `ma.masked_array(in_arr, mask ``=``[[[ ``1``, ``0``]], [[ ``0``, ``0``]]]) ``print` `(``"3D Masked array : "``, mask_arr) ``   ` `# applying MaskedArray.ravel methods to mask array ``out_arr ``=` `mask_arr.ravel() ``print` `(``"1D view of masked array : "``, out_arr) `
Output:
```Input array :  [[[ 2.0e+08  3.0e-05]]

[[-4.5e+01  2.0e+05]]]
3D Masked array :  [[[-- 3e-05]]

[[-45.0 200000.0]]]
1D view of masked array :  [-- 3e-05 -45.0 200000.0]
```

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