How to test if one string is a subsequence of another in python?

How to test if one string is a subsequence of another in python?

You can test if one string is a subsequence of another in Python by iterating through the characters of both strings while keeping track of the current position in both strings. Here's how you can do it:

def is_subsequence(s, t): s_idx = 0 # Index for string s t_idx = 0 # Index for string t while s_idx < len(s) and t_idx < len(t): if s[s_idx] == t[t_idx]: s_idx += 1 t_idx += 1 return s_idx == len(s) # Test cases print(is_subsequence("abc", "ahbgdc")) # True, "abc" is a subsequence of "ahbgdc" print(is_subsequence("axc", "ahbgdc")) # False, "axc" is not a subsequence of "ahbgdc"

In this example, the is_subsequence function takes two strings s and t. It uses two indices, s_idx and t_idx, to traverse the characters of both strings. If the characters at the current positions match, the s_idx is incremented to move to the next character in s. The t_idx is always incremented to continue iterating through t.

The function returns True if the entire s string has been matched, indicating that s is a subsequence of t. Otherwise, it returns False.

This approach has a time complexity of O(n), where n is the length of the longer string (t in this case). It's an efficient way to determine if one string is a subsequence of another.

Examples

  1. "Python: Check if String is Subsequence of Another String"

    Description: Users often look for methods to determine if one string is a subsequence of another in Python. This code compares the characters of both strings to find if the second string is a subsequence of the first.

    # Code Implementation: def is_subsequence(s, t): i, j = 0, 0 while i < len(s) and j < len(t): if s[i] == t[j]: j += 1 i += 1 return j == len(t)

  2. "Python: Test String Subsequence with Index Search"

    Description: Demonstrating how to use index search to test if one string is a subsequence of another in Python.

    # Code Implementation: def is_subsequence(s, t): pos = 0 for char in t: pos = s.find(char, pos) + 1 if not pos: return False return True

  3. "Python: Verify String Subsequence with Iteration"

    Description: Showing an iterative approach to verify if one string is a subsequence of another in Python.

    # Code Implementation: def is_subsequence(s, t): t_iter = iter(t) return all(char in t_iter for char in s)

  4. "Python: Check String Subsequence Using List Comprehension"

    Description: Utilizing list comprehension to check if one string is a subsequence of another in Python.

    # Code Implementation: def is_subsequence(s, t): return all(char in t for char in s)

  5. "Python: Test String Subsequence with Sequence Matching"

    Description: Demonstrating how to use sequence matching to test if one string is a subsequence of another in Python.

    # Code Implementation: from difflib import SequenceMatcher def is_subsequence(s, t): return SequenceMatcher(None, s, t).find_longest_match(0, len(s), 0, len(t)).size == len(s)

  6. "Python: Verify String Subsequence with Recursive Approach"

    Description: Showing a recursive approach to verify if one string is a subsequence of another in Python.

    # Code Implementation: def is_subsequence(s, t): if len(s) == 0: return True if len(t) == 0: return False if s[0] == t[0]: return is_subsequence(s[1:], t[1:]) return is_subsequence(s, t[1:])

  7. "Python: Check String Subsequence with Dynamic Programming"

    Description: Utilizing dynamic programming to check if one string is a subsequence of another in Python.

    # Code Implementation: def is_subsequence(s, t): dp = [[0] * (len(t) + 1) for _ in range(len(s) + 1)] for i in range(1, len(s) + 1): for j in range(1, len(t) + 1): if s[i - 1] == t[j - 1]: dp[i][j] = dp[i - 1][j - 1] + 1 else: dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]) return dp[-1][-1] == len(s)

  8. "Python: Test String Subsequence with Set Intersection"

    Description: Demonstrating how to use set intersection to test if one string is a subsequence of another in Python.

    # Code Implementation: def is_subsequence(s, t): return set(s).intersection(set(t)) == set(s)

  9. "Python: Verify String Subsequence with Sliding Window"

    Description: Showing a sliding window approach to verify if one string is a subsequence of another in Python.

    # Code Implementation: def is_subsequence(s, t): if not s: return True i, j = 0, 0 while i < len(s) and j < len(t): if s[i] == t[j]: i += 1 j += 1 return i == len(s)

  10. "Python: Check String Subsequence with Itertools"

    Description: Utilizing itertools to check if one string is a subsequence of another in Python.

    # Code Implementation: from itertools import islice def is_subsequence(s, t): it = iter(t) return all(char in it for char in s)

More Tags

git-tower gstreamer audio-streaming binary-search-tree bulma frequency copy-paste android-preferences primes oop

More Python Questions

More Housing Building Calculators

More Internet Calculators

More Transportation Calculators

More Entertainment Anecdotes Calculators