(self, haystack: str, needle: str) -> int: needle_len = len(needle) # status transfer function kmp = {0: {needle[0]: 1}} # kmp = {cur_status: {cur_char: next_status}} pre_status = 0 # backward status, init as 0 for status in range(1, needle_len): for l in needle: ...
def find_all_occurrences(string, sub): index_of_occurrences = [] current_index = 0 while True: current_index = string.find(sub, current_index) if current_index == -1: return index_of_occurrences else: index_of_occurrences.append(current_index) current_index += len(sub) find_all_occurr...
deffind_second_occurrence(string,target):first_occurrence=string.find(target)second_occurrence=string.find(target,first_occurrence+1)returnsecond_occurrence 1. 2. 3. 4. 在这个函数中,我们首先使用find()方法找到目标字符的第一次出现位置,然后使用find()方法再次查找目标字符,并指定起点为第一次出现位置后...
# Last Occurrence of a Character in a String without using inbuilt functions str = input("Enter a string : ") char = input("Enter a character to serach in string : ") flag = 0 count = 0 for i in range(len(str)): if str[i] == char: flag = i if flag == 0: print("E...
The last occurrence of 'Hello' in 'Hello, world! Hello' is at index 14. 1. 在上面的示例代码中,我们首先导入了re模块,然后定义了一个字符串str1和一个子串substring。接下来,使用re.findall()函数查找子串在字符串中的所有出现,并将结果保存在变量match中。由于match是一个列表,我们可以通过match[-1]...
Python Regular Expression: Exercise-22 with SolutionWrite a Python program to find the occurrence and position of substrings within a string.Sample Solution:Python Code:import re text = 'Python exercises, PHP exercises, C# exercises' pattern = 'exercises' for match in re.finditer(pattern, text)...
Use there.finditer()Function to Find All Occurrences of a Substring in a String re.finditer()is a function of the regex library that Python provides for programmers to use in their code. It helps in performing the task of finding the occurrence of a particular pattern in a string. To use...
returns the lowest index of the substring if it is found in given string. If it’s not found then it returns -1. 代码1 word ='geeks for geeks'# returns first occurrence of Substringresult = word.find('geeks')print("Substring 'geeks' found at index:", result ) ...
def find_first_occurrence(lst, target): for i in range(len(lst)): if lst[i] == target: return i return -1 # 如果字符串不存在于列表中,返回-1 # 示例用法 my_list = ['apple', 'banana', 'orange', 'apple', 'grape'] target_string = 'apple' result = find_first_occurrence(my_...
Thefind()method returns the index of first occurrence of the substring (if found). If not found, it returns-1. Example message ='Python is a fun programming language' # check the index of 'fun'print(message.find('fun')) # Output: 12 ...