"Python Core programming second Edition" after class exercise 6-12 answers

Afternoon brain Watt, thought for a while did not come up with algorithms, just convulsions finally realized, hereby recorded. ￣-￣| |

Topic

(a) Create a function with the name FINDCHR (), FINDCHR () to find the character char in string strings, find the index that returns the value, otherwise return-1.

(b) Create another function called RFINDCHR (), looking for the character char last occurrence. It works like FINDCHR (), but it looks forward from the end of the string.

(c) Create a third function, called SUBCHR (), SUBCHR () similar to FINDCHR (), and the difference is that if a matching character is found, the original character is replaced with a new one. Returns the modified string.

Note: You cannot use the String.*find () or String.*index () functions and methods

Def findchr (String, char):    if char in string:        i=0 while        String[i:i+len (char)]!=char:            i+=1        Else:            return i    else:        return-1        def rfindchr (String, char):    if char in string:        i=0 while        i< (Len (String)-len (char) +1):            if String[i:i+len (char)]!=char:                i+=1            Else:                s=i                i+=1        Else:            return s    else:        return-1def subchr (String, Origchar, Newchar):    if Origchar in string:        I =0 while        String[i:i+len (Origchar)]!=origchar:            i+=1        Else:            new_string=string[:i]+newchar+ string[(I+len (Origchar)):]            return new_string    else:        return-1

　　

#运行结果print (FINDCHR (' xabcxxxx ', ' abc ') Print (RFINDCHR (' abcxxxxabc ', ' abc ')) Print (SUBCHR (' abcxxxx ', ' abc ', ' Lilip ')) 17lilipxxxx

　　

"Python Core programming second Edition" after class exercise 6-12 answers