源碼: simple.py
# -.- coding:utf-8 -.-
#
# 檢查一個字符是否包含另外一個字符.
#
# 相似功能, in 關(guān)鍵字, 舉例:
# if "a" in "abc":
# return True
# else:
# return False
from __future__ import print_function
def in_(letters, find):
"""
:return: True or False
"""
# 字符集的總長度
letters_len = len(letters)
# 匹配關(guān)鍵字的總長度
find_len = len(find)
# 利用分片, 從
# 0: 0+find_len
# 1: 1+find_len
# 2: 2+find_len
# ...
# 以此類推去查找.
for i in range(letters_len):
print(i)
if letters[i:i+find_len] == find:
return True
# 未命中則返回False
return False
if __name__ == '__main__':
print(in_("abcdefg", "fg"))
# 一共查找了7次
# output
0
1
2
3
4
5
6
False
?
?
源碼: optimize.py
# -.- coding:utf-8 -.-
#
# 檢查一個字符是否包含另外一個字符.
#
# 相似功能, in 關(guān)鍵字, 舉例:
# if "a" in "abc":
# return True
# else:
# return False
from __future__ import print_function
def in_(letters, find):
letters_len = len(letters)
find_len = len(find)
max_index = letters_len - find_len
for i in range(max_index + 1):
print(i)
if letters[i:i+find_len] == find:
return True
return False
if __name__ == '__main__':
print(in_("abcdefg", "fg"))
# 一共查找了6次
# output
0
1
2
3
4
5
True
?
?
源碼: final.py
# -.- coding:utf-8 -.-
# 檢查一個字符是否包含另外一個字符.
from __future__ import print_function
# 不采用分片的寫法.
def has_substring(search, find):
if not search:
return bool(find)
max_search_index = len(search) - len(find)
for i in range(0, max_search_index+1):
found = True
for j in range(0, len(find)):
if search[i+j] != find[j]:
found = False
break
if found:
return found
return False
if __name__ == '__main__':
print(has_substring("abcdefg", "gh"))
