Given a string and a number ‘n’, the task is to remove a string of length ‘n’ from the start of the string. Let’s a few methods to solve the given task.
Method #1: Using Naive Method
# Python3 code to demonstrate # how to remove 'n' characters from starting # of a string # Initialising string ini_string1 = 'garg_akshat'
# Initialising number of characters to be removed n = 5
# Printing initial string print ( "Initial String" , ini_string1)
# Removing n characters from string using # Naive method res = ''
for i in range ( 0 , len (ini_string1)):
if i > = n:
res = res + ini_string1[i]
# Printing resultant string print ( "Resultant String" , res)
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Initial String garg_akshat Resultant String akshat
Time Complexity: O(n)
Auxiliary Space: O(n)
Method #2: Using replace()
# Python3 code to demonstrate # how to remove 'n' characters from starting # of a string # Initialising string ini_string1 = 'garg_akshat'
# Initialising number of characters to be removed n = 5
# Printing initial string print ( "Initial String" , ini_string1)
# Removing n characters from string using # replace() function res = ini_string1.replace(ini_string1[: 5 ], '', 1 )
# Printing resultant string print ( "Resultant String" , res)
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Initial String garg_akshat Resultant String akshat
Time Complexity: O(n)
Auxiliary Space: O(n)
Method #3: String slicing
# Python3 code to demonstrate # how to remove 'n' characters from starting # of a string # Initialising string ini_string1 = 'gargakshat123'
# Initialising number of characters to be removed n = 5
# Printing initial string print ( "Initial String" , ini_string1)
# Removing n characters from a string # This argument count length from zero # So length to be stripped is passed n-1 res = ini_string1[ 4 :]
# Printing resultant string print ( "Resultant String" , res)
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Initial String gargakshat123 Resultant String akshat123
Time Complexity: O(n)
Auxiliary Space: O(n)
Using the join() method and a list comprehension:
Approach:
In this example, we have a string variable containing the original string and an n variable containing the number of characters we want to remove from the start of the string. We pass these variables as arguments to the remove_n_chars_from_start() function and store the result in the new_string variable. Finally, we print the new_string variable to see the resulting string after removing n characters from the start.
def remove_n_chars_from_start(string, n):
return ''.join([string[i] for i in range (n, len (string))])
string = "hello world"
n = 3
new_string = remove_n_chars_from_start(string, n)
print (new_string) # Output: "lo world"
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lo world
Time Complexity: O(n), where n is the length of the string
Space Complexity: O(n)