CODEWITHSUNDEEP
pythonpython-3.xpalindrome
Mehdi Rizvi
Mehdi Rizvi

Reputation: 13

Whether the input is a palidrome or not

So, i am writing a code to check whether the entered string is a palindrome or not, i have written the following code, but its not working properly, for e.g, if i input "race" it still says TRUE, although it should say FALSE, Please help. This is the code

string = input("Please enter any word: ")
a = 0
string_length = len(string)
for string_index in range(string_length-1, -1, -1):
    character = string[string_index]
    if string[a] == character:
        a = a + 1
        b = "TRUE"
    else:
        b = "FALSE"
print(b)

Upvotes: 1

Views: 115

Answers (3)

מתן ל
מתן ל

Reputation: 234

The correct code:

a = 0
string_length = len(string)
for string_index in range(string_length-1, -1, -1):
    character = string[string_index]
    if string[a] == character:
        a = a + 1
        b = "TRUE"
    else:
        b = "FALSE"
        break;  # this line was missing
print(b)

Upvotes: 2

user5777975
user5777975

Reputation: 

string = input("Please enter any word: ")
string_length = len(string)
start_index = 0
count = 0 
end_index = string_length - 1
for string_index in range(int(string_length/2)):
    if string[start_index] == string[end_index]:
        start_index = start_index + 1
        end_index = end_index - 1
        count += 1
    else:
        pass
print("Palendrome") if count == int(string_length/2) else print("Not Palendrome")

Explanation: To check for palendrome string compare the first and last character upto the comparison comes to middle of string

for string_index in range(int(string_length/2)):

compare the first character and last character:

if string[start_index] == string[end_index]:

Update the start_index and end_index and count:

start_index = start_index + 1
end_index = end_index - 1
count += 1

If count is equal to half the length of string then it is definitely a Palendrome

print("Palendrome") if count == int(string_length/2) else print("Not Palendrome")

Upvotes: 0

Patrick Artner
Patrick Artner

Reputation: 51643

In addition to this answer by מתן ל:

You can easily compare your input agains itself when reversed - list comprehension makes this trivial:

Simple 1-word and case-aware test:

word = "SomemoS"
print(word == word[::-1])  # word[::-1] simply reverses the word and prints True if same

Case insensitive and allow punctuation

A palindrom is readable from both sides. Depending on the rules for palindrom-ness you might allow for ignored casing and even eleminate whitespaces and punctuation marks.

  • apply lower() to it
  • do not care about whitespace and punctuation 
word = [c.lower() for c in "No, it can assess an action." if c not in ',. !?']
print(word == word[::-1])  # True as well

Upvotes: 2

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