Python Program to Add K between case shifts

In Python, we can add a symbol between case shifts (transitions from uppercase to lowercase or vice versa) using built-in string methods like isupper(), islower(), and join(). A case shift occurs when consecutive characters change from uppercase to lowercase or lowercase to uppercase.

Understanding Case Shifts

Let's see what case shifts look like with an example ?

# Example of case shifts in a string
text = "tUtoRialsPoInt"
print("Original string:", text)
print("Case shifts occur between:")
print("t -> U (lowercase to uppercase)")
print("U -> t (uppercase to lowercase)")  
print("o -> R (lowercase to uppercase)")

Original string: tUtoRialsPoInt
Case shifts occur between:
t -> U (lowercase to uppercase)
U -> t (uppercase to lowercase)
o -> R (lowercase to uppercase)

Method 1: Using For Loop with isupper() and islower()

The isupper() method returns True if all characters are uppercase, while islower() returns True if all characters are lowercase ?

# Input string and symbol
input_string = 'tUtoRialsPoInt'
k = '#'

print("Input String:", input_string)

# Result string to store the output
result_str = ""

# Traverse through the string (excluding last character)
for i in range(len(input_string) - 1):
    current_char = input_string[i]
    next_char = input_string[i + 1]
    
    # Check for case shifts
    if (current_char.isupper() and next_char.islower()) or (current_char.islower() and next_char.isupper()):
        result_str += current_char + k
    else:
        result_str += current_char

# Add the last character
result_str += input_string[-1]

print("Resultant String after adding # between case shifts:", result_str)

Input String: tUtoRialsPoInt
Resultant String after adding # between case shifts: t#U#to#R#ials#P#o#I#nt

Method 2: Using List Comprehension

List comprehension provides a concise way to create lists and can be combined with join() to build strings ?

# Input string and symbol  
input_string = 'tUtoRialsPoInt'
k = '#'

print("Input String:", input_string)

# Use list comprehension to add k between case shifts
result_str = ''.join([
    input_string[i] + k 
    if (input_string[i].isupper() and input_string[i + 1].islower()) or 
       (input_string[i].islower() and input_string[i + 1].isupper())
    else input_string[i] 
    for i in range(len(input_string) - 1)
])

# Add the last character
result_str += input_string[-1]

print("Resultant String after adding # between case shifts:", result_str)

Input String: tUtoRialsPoInt
Resultant String after adding # between case shifts: t#U#to#R#ials#P#o#I#nt

Comparison

Conclusion

Both methods effectively add symbols between case shifts using isupper() and islower() to detect transitions. The for loop approach is more readable for beginners, while list comprehension offers a more concise solution for experienced Python developers.