Remove leading zeros from a Number given Using Space-Efficient Approach
Follow the steps below to solve the problem in constant space using Regular Expression:
- Create a Regular Expression as given below to remove the leading zeros
regex = “^0+(?!$)”
where:
^0+ match one or more zeros from the beginning of the string.
(?!$) is a negative look-ahead expression, where “$” means the end of the string.
- Use the inbuilt replaceAll() method of the String class which accepts two parameters, a Regular Expression, and a Replacement String.
- To remove the leading zeros, pass a Regex as the first parameter and empty string as the second parameter.
- This method replaces the matched value with the given string.
Below is the implementation of the above approach:
Python3
# Python3 Program to implement # the above approach import re # Function to remove all leading # zeros from a given string def removeLeadingZeros(str): # Regex to remove leading # zeros from a string regex = "^0+(?!$)" # Replaces the matched # value with given string str = re.sub(regex, "", str) print(str) # Driver Code str = "0001234"removeLeadingZeros(str) |
Output
1234
Time Complexity: O(N), where N is the length of the string.
Auxiliary Space: O(1)
Python Program for Remove leading zeros from a Number given as a string
Given numeric string str, the task is to remove all the leading zeros from a given string. If the string contains only zeros, then print a single “0”.
Examples:
Input: str = “0001234”
Output: 1234
Explanation:
Removal of leading substring “000” modifies the string to “1234”.
Hence, the final answer is “1234”.Input: str = “00000000”
Output: 0
Explanation:
There are no numbers except 0
Contact Us