# numpy.atleast_3d() in Python

`numpy.atleast_3d()` function is used when we want to Convert inputs to arrays with at least three dimension. Scalar, 1 and 2 dimensional inputs are converted to 3-dimensional arrays, whilst higher-dimensional inputs are preserved.

Input includes scalar, lists, lists of tuples, tuples, tuples of tuples, tuples of lists and ndarrays.

Syntax : numpy.atleast_3d(*arrays)

Parameters :
arrays1, arrays2, … : [array_like] One or more array-like sequences. Non-array inputs are converted to arrays. Arrays that already have three or more dimensions are preserved.

Return : An array, or list of arrays, each with arr.ndim >= 3. Copies are avoided where possible, and views with three or more dimensions are returned. For example, a 1-D array of shape (N, ) becomes a view of shape (1, N, 1), and a 2-D array of shape (M, N) becomes a view of shape (M, N, 1).

Code #1 : Working

 `# Python program explaining ` `# numpy.atleast_3d() function ` `  `  `import` `numpy as geek ` `in_num ``=` `10` `  `  `print` `(``"Input  number : "``, in_num) ` `   `  `    `  `out_arr ``=` `geek.atleast_3d(in_num) ` `print` `(``"output 3d array from input number : "``, out_arr)  `

Output :

```Input  number :  10
output 3d array from input number :  [[]]
```

Code #2 : Working

 `# Python program explaining ` `# numpy.atleast_3d() function ` ` `  `import` `numpy as geek ` ` `  `my_list ``=` `[[``2``, ``6``, ``10``],  ` `          ``[``8``, ``12``, ``16``]] ` `  `  `print` `(``"Input  list : "``, my_list) ` `   `  `out_arr ``=` `geek.atleast_3d(my_list)  ` `print` `(``"output array : "``, out_arr)  `

Output :

```Input  list :  [[2, 6, 10], [8, 12, 16]]
output array :  [[[ 2]
[ 6]
]

[[ 8]

]]
```

Code #3 : Working

 `# Python program explaining ` `# numpy.atleast_3d() function ` `# when inputs are in high dimension ` ` `  `import` `numpy as geek ` ` `  `in_arr ``=` `geek.arange(``16``).reshape(``1``, ``4``, ``4``) ` `print` `(``"Input  array :\n "``, in_arr) ` ` `  `out_arr ``=` `geek.atleast_3d(in_arr) ` `print` `(``"output  array :\n "``, out_arr) ` `print``(in_arr ``is` `out_arr) `

Output :

```Input  array :
[[[ 0  1  2  3]
[ 4  5  6  7]
[ 8  9 10 11]
[12 13 14 15]]]
output  array :
[[[ 0  1  2  3]
[ 4  5  6  7]
[ 8  9 10 11]
[12 13 14 15]]]
True
```

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