Array in Python | Set 2 (Important Functions)

Difficulty Level : Easy
Last Updated : 13 May, 2020

Array in Python | Set 1 (Introduction and Functions)

Below are some more functions.

1. typecode :- This function returns the data type by which array is initialised.

2. itemsize :- This function returns size in bytes of a single array element.

3. buffer_info() :- Returns a tuple representing the address in which array is stored and number of elements in it.

# Python code to demonstrate the working of 
# typecode, itemsize, buffer_info()
   
# importing "array" for array operations
import array
   
# initializing array with array values
# initializes array with signed integers
arr= array.array('i',[1, 2, 3, 1, 2, 5]) 
  
# using typecode to print datatype of array
print ("The datatype of array is : ")
print (arr.typecode)
  
# using itemsize to print itemsize of array
print ("The itemsize of array is : ")
print (arr.itemsize)
  
# using buffer_info() to print buffer info. of array
print ("The buffer info. of array is : ")
print (arr.buffer_info())

Output:

The datatype of array is : 
i
The itemsize of array is : 
4
The buffer info. of array is : 
(29784224, 6)

Instead of import array, we can also use * to import array.

# importing "array" using * for array operations
from array import *
   
# initializing array with array values
# initializes array with signed integers
arr = array('i',[1, 2, 3, 1, 2, 5]) 
  
print(arr)

Output:

array('i', [1, 2, 3, 1, 2, 5])

4. count() :- This function counts the number of occurrences of argument mentioned in array.

5. extend(arr) :- This function appends a whole array mentioned in its arguments to the specified array.

# Python code to demonstrate the working of 
# count() and extend()
   
# importing "array" for array operations
import array
   
# initializing array 1 with array values
# initializes array with signed integers
arr1 = array.array('i',[1, 2, 3, 1, 2, 5]) 
  
# initializing array 2 with array values
# initializes array with signed integers
arr2 = array.array('i',[1, 2, 3]) 
  
# using count() to count occurrences of 1 in array
print ("The occurrences of 1 in array is : ")
print (arr1.count(1))
  
# using extend() to add array 2 elements to array 1 
arr1.extend(arr2)
  
print ("The modified array is : ")
for i in range (0,9):
    print (arr1[i])

Output:

The occurrences of 1 in array is : 
2
The modified array is : 
1
2
3
1
2
5
1
2
3

6. fromlist(list) :- This function is used to append a list mentioned in its argument to end of array.

7. tolist() :- This function is used to transform an array into a list.

# Python code to demonstrate the working of 
# fromlist() and tolist()
   
# importing "array" for array operations
import array
   
# initializing array with array values
# initializes array with signed integers
arr = array.array('i',[1, 2, 3, 1, 2, 5]) 
  
# initializing list
li = [1, 2, 3]
  
# using fromlist() to append list at end of array
arr.fromlist(li)
  
# printing the modified array
print ("The modified array is : ",end="")
for i in range (0,9):
    print (arr[i],end=" ")
  
# using tolist() to convert array into list
li2 = arr.tolist()
  
print ("\r")
  
# printing the new list
print ("The new list created is : ",end="")
for i in range (0,len(li2)):
    print (li2[i],end=" ")

Output:

The modified array is : 1 2 3 1 2 5 1 2 3 
The new list created is : 1 2 3 1 2 5 1 2 3

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Array in Python | Set 2 (Important Functions)