# Python | Convert list to Python array

Last Updated : 14 Aug, 2023

Sometimes while working in Python we can have a problem in which we need to restrict the data elements to just one type. A list can be heterogeneous, can have data of multiple data types and it is sometimes undesirable. There is a need to convert this to a data structure that restricts the type of data.

# Convert List to Array Python

• Using array() with data type indicator
• Using numpy.array() method

### Convert a list to an array using numpy.array()

This task can be easily performed using the array() function. This is an inbuilt function in Python to convert to an array. The data type indicator “i” is used in the case of integers, which restricts data type.

## Python3

 `# Using array() + data type indicator` `from` `array ``import` `array`   `# initializing list` `test_list ``=` `[``6``, ``4``, ``8``, ``9``, ``10``]`   `# printing list` `print``(``"The original list : "` `+` `str``(test_list))`   `# Convert list to Python array` `# Using array() + data type indicator` `res ``=` `array(``"i"``, test_list)`   `# Printing result` `print``(``"List after conversion to array : "` `+` `str``(res))`

Output

```
The original list : [6, 4, 8, 9, 10]
List after conversion to array : array('i', [6, 4, 8, 9, 10])

```

Time Complexity: O(n), where n is the length of the list test_list
Auxiliary Space: O(n) additional space of size n is created where n is the number of elements in the res list

### Convert Python List to NumPy Arrays using numpy.array()

Converts a Python list to a Python array using the numpy.array() function. It imports the numpy module, initializes a list named test_list, and prints the original list. Then, the numpy.array() function is used to convert test_list to a Python array and store the result in the res variable. Finally, it prints the resulting Python array.

## Python3

 `#Using numpy.array()` `import` `numpy as np`   `#initializing list` `test_list ``=` `[``6``, ``4``, ``8``, ``9``, ``10``]`   `#printing list` `print``(``"The original list : "` `+` `str``(test_list))`   `#Convert list to Python array using numpy.array` `res ``=` `np.array(test_list)`   `#Printing result` `print``(``"List after conversion to array : "` `+` `str``(res))`

Output:

```The original list : [6, 4, 8, 9, 10]
List after conversion to array : [ 6  4  8  9 10]```

Time Complexity: O(n), where n is the length of the list test_list
Auxiliary Space: O(n) as the Python array created by numpy.array() stores the same data as the original list.

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