# Python | Flatten a 2d numpy array into 1d array

Given a 2d numpy array, the task is to flatten a 2d numpy array into a 1d array. Below are a few methods to solve the task.

Method #1 : Using np.flatten()

 `# Python code to demonstrate ` `# flattening a 2d numpy array ` `# into 1d array ` ` `  `import` `numpy as np ` ` `  `ini_array1 ``=` `np.array([[``1``, ``2``, ``3``], [``2``, ``4``, ``5``], [``1``, ``2``, ``3``]]) ` ` `  `# printing initial arrays ` `print``(``"initial array"``, ``str``(ini_array1)) ` ` `  `# Multiplying arrays ` `result ``=` `ini_array1.flatten() ` ` `  `# printing result ` `print``(``"New resulting array: "``, result) `

Output:

```initial array [[1 2 3]
[2 4 5]
[1 2 3]]
New resulting array:  [1 2 3 2 4 5 1 2 3]
```

Method #2: Using np.ravel()

 `# Python code to demonstrate ` `# flattening a 2d numpy array ` `# into 1d array ` ` `  `import` `numpy as np ` ` `  `ini_array1 ``=` `np.array([[``1``, ``2``, ``3``], [``2``, ``4``, ``5``], [``1``, ``2``, ``3``]]) ` ` `  `# printing initial arrays ` `print``(``"initial array"``, ``str``(ini_array1)) ` ` `  `# Multiplying arrays ` `result ``=` `ini_array1.ravel() ` ` `  `# printing result ` `print``(``"New resulting array: "``, result) `

Output:

```initial array [[1 2 3]
[2 4 5]
[1 2 3]]
New resulting array:  [1 2 3 2 4 5 1 2 3]
```

Method #3: Using np.reshape()

 `# Python code to demonstrate ` `# flattening a 2d numpy array ` `# into 1d array ` ` `  `import` `numpy as np ` ` `  `ini_array1 ``=` `np.array([[``1``, ``2``, ``3``], [``2``, ``4``, ``5``], [``1``, ``2``, ``3``]]) ` ` `  `# printing initial arrays ` `print``(``"initial array"``, ``str``(ini_array1)) ` ` `  `# Multiplying arrays ` `result ``=` `ini_array1.reshape([``1``, ``9``]) ` ` `  `# printing result ` `print``(``"New resulting array: "``, result) `

Output:

```initial array [[1 2 3]
[2 4 5]
[1 2 3]]
New resulting array:  [[1 2 3 2 4 5 1 2 3]]
```

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