CODEWITHSUNDEEP
python
etotheipi
etotheipi

Reputation: 49

Check the lexicographic order of two strings in python

I am trying to implement a function in python that given two strings it checks if the first string is smaller than the second string in the lexicographic order. This is what I managed to write, I do not claim that it is elegant code

import string
#first make a dictionary that gives the value of a letter, eg "C":3
d = dict.fromkeys(string.ascii_uppercase, 0)
i=1
for c in d.keys():
    d[c] = i
    i+=1

def lexico(str1,str2):#returns true if str1<=str2 in lexicographic order
    print(str1,str2) #printing for debugging purpose
    if str1 == '' and str2 == '':
        return True
    elif str1 != '' and str2 == '':
        return False
    elif str1 == '' and str2 != '':
        return True
    elif d[str1[0]] > d[str2[0]]:
        return False
    elif d[str1[0]] < d[str2[0]]:
        return True
    elif str1 == str2:
        return True
    else: 
        print(str1,str2) #printing for debugging purpose
        lexico(str1[1:],str2[1:])
str1 = 'ANGELA'
str2 = 'AMY'
print(lexico(str1,str2))

I have really no idea what goes wrong here, but the output is as follows

ANGELA AMY
ANGELA AMY
NGELA MY
None

The function does not return anything, and I dont know why.

Upvotes: 0

Views: 885

Answers (1)

kingkupps
kingkupps

Reputation: 3494

You are missing a return on this line: lexico(str1[1:],str2[1:]). It should be return lexico(str1[1:],str2[1:]).

Upvotes: 2

Related Questions