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Python | Find the frequency of a given character at each position in a list of lists

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For a given list of lists, the task is to find the frequency of the character in each position of the sublist in the 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 items in each sublist, we need to find the position & # 39; X & # 39; at positions 0, 1 and 2. For position 0 in all sublists we have:
"x" in the first sublist at position zero,
& # 39; z & # 39; in the second sublist at position zero,
& # 39; y & # 39; in the third sublist at the zero position,
& # 39; z & # 39; in the fourth sublist at the zero position and
& # 39; y & # 39; in the fifth sublist at position zero.

So, we have 1 occurrence of & # 39; x & # 39; at position 1 in the whole sublist, therefore Occurrence = 1/5 = .2
For position 1 in the sublist there is no occurrence & # 39; x & # 39;, therefore Occurrence = 0/5 = 0.
For Position 2 we have 4 occurrences & # 39; x & # 39; in a sublist, so Occurrence = 4/5 = 0.8

Let’s discuss some of the ways this can be done.

Method # 1: Using Iteration

# Python code to find the frequency of a character
# at each list position in the list of lists.

 
# Initialize the insertion list

Input = [[ ’X ’ , ’ Y’ , ’X’ ], [ ’ Z’ , ’Y’ , ’ X’ ],

  [ ’Y’ , ’ Y’ , ’Y’ ], [ ’ Z’ , ’Z’ , ’ X’ ],

[ ’Y’ , ’ Z’ , ’X’ ]]

Output = []

 
# Character initialization

character = ’X’

  
# Initialize the output list

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 )

  
# Print

print ( "Initial list of list is:" , Input )

print ( "Occurrence of’ X’ in list is " , Output)

Exit:

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 character frequency
# on each sleep position ska in the list of lists.

 
# Initialize the input list

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 )]

 
# Print

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 the frequency of a character
# at each list position in the list of lists.

 

import pandas as pd

 
# Initialize the input list

Input = [[ ’X’ , ’Y’ , ’ X’ ] ,

[ ’Z’ , ’ Y’ , ’X’ ],

[ ’Y’ , ’Y’ , ’ Y’ ],

[ ’Z’ , ’ Z’ , ’X’ ],

  [ ’ Y’ , ’Z’ , ’ X’ ]]

 
# Character definition

character = ’ X’

 
# using pandas

Output = pd.DataFrame ( Input )

Output = Output.where (Output = = character, 0 ). where (Output! = character, 1 )

 
# Print

print ( " Initial list of list is: " , Input )

print ( " Occurrence of ’X’ in list is" , 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

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