check if digit is at same position in two different numbers

Question

Q)write a program to check at which position digits are same and print the position at which they are same.

for example, if n1=1234453 and n2=2444853 print Same at 1's position

Same at 10th position

Same at 1000th position

how to fix this so it works? it display's 3th position instead of 100th?

n1=int(input())
n2=int(input())
ns1=str(n1)
ns2=str(n2)
l1=len(ns1)
for x in ns1:
    for y in ns2:
        if x==y:
            if int(ns1.index(x))==int(ns2.index(y)):
                print("Same at %dth position"%(ns1.index(x)))
            else:
                print("No digits are same")
        else:
            print("No digits are same")

If you have a traceback, please update your question with the full error traceback. — quamrana, Oct 19 '21 at 15:20
@quamrana no error. it was there before but sayandip pointed it out. right now it's just not showing me the correct output — students, Oct 19 '21 at 16:32
Your code as posted has a typo on the first `print(...` line. — quamrana, Oct 19 '21 at 16:42
@quamrana i thought i edited it already i must have forgotten to click save. thank you for pointing it out — students, Oct 19 '21 at 16:44

user2390182 · Accepted Answer · 2021-10-19T16:51:29.117

1

Use zip, enumerate and powers of 10:

ns1 = "1234453"
ns2 = "2444853"

found = False
for i, (x, y) in enumerate(zip(ns1[::-1], ns2[::-1])):
    if x == y:
         found = True
         print(f"Same at {10**i}th position")
    # no else here!! just because of a mismatch at the first digit
    # does not mean there aren't any matches later
if not found:
    print("No digits are same")

# Same at 1th position
# Same at 10th position
# Same at 1000th position

Your nested loops are doing way too much work, looping through the entire second string for each char in the first. zip is much more efficient, just doing a pair-wise (parallel) iteration of both (reversed) strings.

Some docs:

zip
enumerate
slice notation: docs, extensive thread here

edited Oct 19 '21 at 16:51

answered Oct 19 '21 at 15:19

user2390182

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how do zip and enumerate work? and is the [::-1] still an way of indexing or something else? – students Oct 19 '21 at 16:39
I added links to the relevant parts of the documentation. The `[::-1]` is slice notation and just a concise way of reversing strings, lists, etc. – user2390182 Oct 19 '21 at 16:47
okayy thank you sm! – students Oct 20 '21 at 03:35

check if digit is at same position in two different numbers

1 Answers1