Python: Move all spaces to the front of a given string in single traversal

Last update on March 21 2025 12:53:47 (UTC/GMT +8 hours)

Move spaces to front in single traversal.

Write a Python program to move all spaces to the front of a given string in a single traversal.

Visual Presentation:

Sample Solution:

Python Code:

# Function to move spaces to front
def moveSpaces(str1):

  # List comprehension to remove spaces
  no_spaces = [char for char in str1 if char!=' ']
  
  # Get number of spaces
  space = len(str1) - len(no_spaces)

  # Create string with required spaces
  result = ' '*space

  # Return moved spaces + string without spaces
  return result + ''.join(no_spaces)

# Test string
s1 = "Python Exercises"  

# Print original string
print("Original String:\n",s1)

# Print message
print("\nAfter moving all spaces to the front:")

# Print result
print(moveSpaces(s1)) 

Sample Output:

Original String:
 Python Exercises

After moving all spaces to the front:
 PythonExercises

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to traverse a string once and build a new string with all spaces moved to the beginning.
• Write a Python program to implement a single-pass algorithm that separates spaces and non-space characters and then concatenates them with spaces first.
• Write a Python program to use a loop to partition a string into spaces and other characters in one traversal and recombine them.
• Write a Python program to iterate through a string, collecting space characters in one list and others in another, then merge them with spaces at the front.

Python Code Editor:

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