1 a='abcdaac' 2 b='a' 3 c='db' 4 print(b in a) 5 print(c in a)
1 a='abcdefgab' 2 print(a.count('a'))
1 a='abcdefgab' 2 print(a.find('a')) 3 print(a.rfind('a')) 4 print(a.find('x')) 5 print(a.rfind('x'))
a='abcdefgab' print(a.index('b')) print(a.index('x'))