Arrays in Python
In Python, an Array is a collection of similar type of data.
Array in Python can be created by importing the array module.
Syntax:
array(data type, [array list])
Example:
from array import array
nums = array("i", [1, 3, 44, 56, 77, 8])
print("int nums = ", end = "")
for i in range(len(nums)):
print(nums[i], end = " ")
print()
nums = array("d", [1.3, 3.5, 44.46, 56.3])
print("double nums = ", end = "")
for i in range(len(nums)):
print(nums[i], end = " ")
Output:
int nums = 1 3 44 56 77 8 double nums = 1.3 3.5 44.46 56.3
While creating an array, the first argument you need to provide is the data type of the array values. The following table will help you create arrays of different types:
Type Code | C Type | Python Type | Minimum Size in bytes |
'b' | signed char | int | 1 |
'B' | unsigned char | int | 1 |
'u' | Py_UNICODE | Unicode Character | 2 |
'h' | signed short | int | 2 |
'H' | unsigned short | int | 2 |
'i' | signed int | int | 2 |
'I' | unsigned int | int | 4 |
'l' | unsigned long | int | 4 |
'L' | unsigned long | int | 4 |
'f' | float | int | 4 |
'd' | double | int | 8 |
Array Methods
Here are some useful array methods in Python:
Method | Description |
append() | Adds an item at the end of an array. |
clear() | Removes all items from an array. |
count() | Returns the number of items in an array. |
copy() | Return copy of an array. |
extend() | Adds multiple items at the end of an array. |
insert() | Adds an item at the specified index of an array. |
pop() | Removes an item from the specified index of an array. |
remove() | Removes the specified item from an array. |
reverse() | Reverses the order of items in an array. |
sort() | Sorts the order of items in an array. |
Adding Items
In Python, you can use the append() method to add items to an array.
Example:
from array import array
# Creating an array
nums = array("i")
# Adding new values
nums.append(55)
nums.append(56)
nums.append(57)
nums.append(58)
for i in range(len(nums)):
print(nums[i], end = " ")
Output:
55 56 57 58
In Python, you can also insert a value at a specified index using the insert() method.
Here's an example of inserting the value 55 at index 0:
from array import array
nums = array("i", [1, 2, 3, 4, 5, 6])
print("nums before = ", end = "")
for i in range(len(nums)):
print(nums[i], end = " ")
print()
# Adding new value to a specified index
nums.insert(0,55)
print("nums after = ", end = "")
for i in range(len(nums)):
print(nums[i], end = " ")
The output of the above code is as follows:
nums before = 1 2 3 4 5 6 nums after = 55 1 2 3 4 5 6
Accessing Array Items
In Python, you can access values of an array by using square brackets with an index.
Example:
from array import array
nums = array("i", [1, 3, 44, 56, 77, 8])
print(nums[0])
print(nums[2])
Output:
1 44
Removing Array Items
In Python, you can remove items from an array using the remove() method.
Example:
from array import array
nums = array("i", [1, 3, 44, 56, 77, 8])
print("nums before = ", end = "")
for i in range(len(nums)):
print(nums[i], end = " ")
print()
#remove value
nums.remove(77)
print("nums after removing = ", end = "")
for i in range(len(nums)):
print(nums[i], end = " ")
Output:
nums before = 1 3 44 56 77 8 nums after removing = 1 3 44 56 8
In Python, you can also remove items at a specified index using the pop() method.
Example:
from array import array
nums = array("i", [1, 3, 44, 56, 77, 8])
print("nums before = ", end = "")
for i in range(len(nums)):
print(nums[i], end = " ")
print()
#removing value at specified index
nums.pop(2)
print("nums after = ", end = "")
for i in range(len(nums)):
print(nums[i], end = " ")
Output:
nums before = 1 3 44 56 77 8 nums after = 1 3 56 77 8