Python | Find frequency of given character at every position in list of lists

Given a list of lists, the task is to find the frequency of a character at every position of sub-list in list of lists.

Input : lst = [['X', 'Y', 'X'], ['Z', 'Y', 'X'],
               ['Y', 'Y', 'Y'], ['Z', 'Z', 'X'],
               ['Y', 'Z', 'X']], character = 'X'

Output: [0.2, 0.0, 0.8]

Explanation:
We have 3 elements in each sublist, we have to find position of ‘X’ at position 0, 1 and 2. For Position 0 in all sublist we have –
‘x’ in first sub list at zero position,
‘z’ in second sub list at zero position,
‘y’ in third sub list at zero position,
‘z’ in fourth sub list at zero position and
‘y’ in fifth sub list at zero position.

So, we have 1 occurrence of ‘x’ at position 1 in all sub list so, Occurrence = 1/5 = .2
For Position 1 we don’t have any occurrence of ‘x’ in sub list so, Occurrence = 0/5 = 0.
For Position 2 we have 4 occurrence of ‘x’ in sub list so, Occurrence = 4/5 = 0.8

Let’s discuss certain ways in which this can be performed.

Method #1 : Using Iteration

# Python code to find frequency of a character 
# at every position of list in list of lists. 
  
# Input list initialization 
Input = [['X', 'Y', 'X'], ['Z', 'Y', 'X'], 
         ['Y', 'Y', 'Y'], ['Z', 'Z', 'X'], 
         ['Y', 'Z', 'X']] 
Output = [] 
  
# Character Initialization 
character = 'X'
  
# Output list initialization 
for elem in range(len(Input[0])): 
    Output.append(0) 
  
# Using iteration 
for elem in Input: 
    for x, y in enumerate(elem): 
        if y == character: 
            Output[x]+= 1
for x, y in enumerate(Output): 
    Output[x] = y / len(Input) 
  
# Printing 
print("Initial list of list is :", Input) 
print("Occurrence of 'X' in list is", Output) 

Output:

Initial list of list is : [[‘X’, ‘Y’, ‘X’], [‘Z’, ‘Y’, ‘X’], [‘Y’, ‘Y’, ‘Y’], [‘Z’, ‘Z’, ‘X’], [‘Y’, ‘Z’, ‘X’]]
Occurrence of ‘X’ in list is [0.2, 0.0, 0.8]

Method #2 : Using zip

# Python code to find frequency of a character 
# at every position of list in list of lists. 
  
# Input list initialization 
Input = [['X', 'Y', 'X'], ['Z', 'Y', 'X'], 
         ['Y', 'Y', 'Y'], ['Z', 'Z', 'X'], 
         ['Y', 'Z', 'X']] 
  
Output = [] 
  
# Character initialization 
character = 'X'
  
# Using zip 
Output = [elem.count(character)/len(elem) 
                 for elem in zip(*Input)] 
  
# Printing 
print("Initial list of list is :", Input) 
print("Occurrence of 'X' in list is", Output) 

Output:

Initial list of list is : [[‘X’, ‘Y’, ‘X’], [‘Z’, ‘Y’, ‘X’], [‘Y’, ‘Y’, ‘Y’], [‘Z’, ‘Z’, ‘X’], [‘Y’, ‘Z’, ‘X’]]
Occurrence of ‘X’ in list is [0.2, 0.0, 0.8]

Method #3: Using Pandas

# Python code to find frequency of a character 
# at every position of list in list of lists. 
  
import pandas as pd 
  
# Input list initialization 
Input = [['X', 'Y', 'X'], 
      ['Z', 'Y', 'X'], 
      ['Y', 'Y', 'Y'], 
      ['Z', 'Z', 'X'], 
      ['Y', 'Z', 'X']] 
  
# Defining character 
character = 'X'
  
# using pandas 
Output = pd.DataFrame(Input) 
Output = Output.where(Output == character, 0).where(Output != character, 1) 
  
# Printing 
print("Initial list of list is :", Input) 
print("Occurrence of 'X' in list is\n", Output.mean()) 

Output:

Initial list of list is : [[‘X’, ‘Y’, ‘X’], [‘Z’, ‘Y’, ‘X’], [‘Y’, ‘Y’, ‘Y’], [‘Z’, ‘Z’, ‘X’], [‘Y’, ‘Z’, ‘X’]]
Occurrence of ‘X’ in list is
0 0.2
1 0.0
2 0.8
dtype: float64

My Personal Notes

Recommended Posts: