Q:

Python program to find the frequency of each element in the array

belongs to collection: Python Array Programs

robaa
Save to bookmark
|
2022-11-07
|
  159 
0

In this program, we have an array of elements to count the occurrence of its each element. One of the approaches to resolve this problem is to maintain one array to store the counts of each element of the array. Loop through the array and count the occurrence of each element as frequency and store it in another array fr.

1    2   8  3   2   2   2   5   1  

In the given array, 1 has appeared two times, so its frequency is 2, and 2 has appeared four times so have frequency 4 and so on.

ALGORITHM:

  • STEP 1: Declare and initialize an array arr.
  • STEP 2: Declare another array fr with the same size of array arr. It is used to store the frequencies of elements present in the array.
  • STEP 3: Variable visited will be initialized with the value -1. It is required to mark an element visited that is, it helps us to avoid counting the same element again.
  • STEP 4: The frequency of an element can be counted using two loops. One loop will be used to select an element from an array, and another loop will be used to compare the selected element with the rest of the array.
  • STEP 5: Initialize count to 1 in the first loop to maintain a count of each element. Increment its value by 1 if a duplicate element is found in the second loop since we have counted this element and didn't want to count it again. Mark this element as visited by setting fr[j] = visited. Store count of each element to fr.
  • STEP 6: Finally, print out the element along with its frequency.
Python programming, examples, Python programming examples,
login and add your own answer to this question

All Answers

robaa
2022-11-07
need an explanation for this answer? contact us directly to get an explanation for this answer 

#Initialize array     
arr = [1, 2, 8, 3, 2, 2, 2, 5, 1];     
#Array fr will store frequencies of element    
fr = [None] * len(arr);    
visited = -1;    
     
for i in range(0, len(arr)):    
    count = 1;    
    for j in range(i+1, len(arr)):    
        if(arr[i] == arr[j]):    
            count = count + 1;    
            #To avoid counting same element again    
            fr[j] = visited;    
                
    if(fr[i] != visited):    
        fr[i] = count;    
     
#Displays the frequency of each element present in array    
print("---------------------");    
print(" Element | Frequency");    
print("---------------------");    
for i in range(0, len(fr)):    
    if(fr[i] != visited):    
        print("    " + str(arr[i]) + "    |    " + str(fr[i]));    
print("---------------------");

 

Output:

----------------------------------------
Element | Frequency
----------------------------------------
1           |         2
2           |         4
8           |         1
3           |         1
5           |         1
----------------------------------------

need an explanation for this answer? contact us directly to get an explanation for this answer

total answers (1)

Python Array Programs
This question belongs to these collections

Similar questions

need a help?

find thousands of online teachers now
Python program to left rotate the elements of an a... >>
<< Python program to copy all elements of one array i...