Combine similar characters in Python using Dictionary Get() Method

Let us see how to combine similar characters in a list. 

Example :

Input : [‘g’, ‘e’, ‘e’, ‘k’, ‘s’, ‘f’, ‘o’, ‘r’, ‘g’, ‘e’, ‘e’, ‘k’, ‘s’] 

Output : [‘gg’, ‘eeee’, ‘kk’, ‘ss’, ‘f’, ‘o’, ‘r’]

We will be using the get() method of the dictionary class.

dictionary.get()

The get() method returns the value of the item with the specified key.

Syntax : dictionary.get(key name, value) 

Parameters :

• keyname : The key name of the dictionary item.
• value : (Optional) If the specified key does not exist, then a value is returned.

Returns : Value of the item with the specified key

Algorithm :

1. Declare the list.
2. Declare a dictionary.
3. Iterate over the list, using the get() method, if a new key is found, then the value 0 is assigned to it and 1 is added making the final value 1. Else if the key is repeated, then 1 is added to the previously calculated value. So this way, now each key has a value assigned to it, and frequency of all characters is recorded.
4. Separate all the keys and the values and store them in 2 different lists.
5. Use the zip() function store the product of keys and their respective values in the result list.
6. Display the result.

Example 1 :

python3

# declaring the list of characters
mylist = ['g', 'e', 'e', 'k', 's', 'f',
          'o', 'r', 'g', 'e', 'e', 'k', 's']

# declaring the dictionary
dictionary = {}

# counting the frequency of the keys
for key in mylist:
    dictionary[key] = dictionary.get(key, 0) + 1

# storing the of keys and values
k = list(dictionary.keys())
v = list(dictionary.values())

# declaring the result list
result = []

# storing the product of keys and
# their respective values in result
for i, j in zip(k, v):
    result.append(i * j)

# displaying the result
print(result)

Output :

['gg', 'eeee', 'kk', 'ss', 'f', 'o', 'r']

Example 2 :

python3

# declaring the list of characters
mylist = ['p', 'y', 't', 'h', 'o', 'n', 't',
          'u', 't', 'o', 'r', 'i', 'a', 'l']

# declaring the dictionary
dictionary = {}

# counting the frequency of the keys
for key in mylist:
    dictionary[key] = dictionary.get(key, 0) + 1

# storing the of keys and values
k = list(dictionary.keys())
v = list(dictionary.values())

# declaring the result list
result = []

# storing the product of keys and
# their respective values in result
for i, j in zip(k, v):
    result.append(i * j)

# displaying the result
print(result)

Output :

['a', 'h', 'i', 'l', 'n', 'oo', 'p', 'r', 'ttt', 'u', 'y']