Return empty string as True in given string

Question

def first_and_last(message):
    if (message[0] == message[3]):
        return True
    elif (message[0] != message[3]):
        return False

print(first_and_last("else"))
print(first_and_last("tree"))
print(first_and_last(""))

I want to return True if string is empty, True if 1st and last letter of string match and False otherwise.

How can I get a True result for an empty string?

Answer 1

• You wrote that you want to compare the first character to the last, so you have to use [-1] and not [3]. Otherwise you are comparing the first and the fourth characters.

• You can use if not message to check if it's an empty string

• Since you are returning, you don't need to check if they do not match.

def first_and_last(message):
    if not message:
        return True
    return message[0] == message[-1]

As noted in the comments this can be pushed a bit more into a single line:

def first_and_last(message):
    return not message or message[0] == message[-1]

Answer 2

You can use if not

def first_and_last(message):
if not message:
    return False
else: return True


print(first_and_last("else")) #True
print(first_and_last("tree")) #True
print(first_and_last("")) #False

Answer 3

# defines, name and establishes the arguments for the function
def first_and_last(message):
 
    # "if not message" checks if the parameter is empty
    # message[0] gets the first character in the parameter
    # message[-1] gets the last character in the parameter
    # "==" checks if the first and last character are the same in the 
    # parameter
    # the "or" comparator checks if the statements on either side or 
    # the comparator is true 

    if not message or message[0] == message[-1]:
        # if either one or both of the above statements are true the 
        # function returns True

        return True
    # otherwise returns False

    return False

Answer 4

You can use if not message: to check if the message variable is empty.

You could, for example, do as follow :

def first_and_last(message):
    if not message:
        return True
    elif (message[0] == message[3]):
            return True
    elif (message[0] != message[3]):
            return False


print(first_and_last("else"))
print(first_and_last("tree"))
print(first_and_last(""))

Answer 5

You can check if the string is empty with bool(message). And check the last item with message[-1]:

def first_and_last(message):
    if not message:
        return True
    elif (message[0] == message[-1]):
        return True
    else:
        return False


print(first_and_last("else")) # Returns True
print(first_and_last("tree")) # Returns False
print(first_and_last("")) # Returns True

Answer 6

Use:

if not message:

This will return true if the string is empty:

def first_and_last(message):
        if not message:
            return True
        if (message[0] == message[3]):
            return True
        elif (message[0] != message[3]):
            return False


print(first_and_last("else"))
print(first_and_last("tree"))
print(first_and_last(""))

Answer 7

def first_and_last(message):
    if not message:
        return True
    elif (message[0] == message[-1]):
        return True
    elif (message[0] != message[-1]):
        return False


print(first_and_last("else"))
print(first_and_last("tree"))
print(first_and_last(""))

Answer 8

def first_and_last(message):

if message=="" or message[0]==message[-1]:

    return True

return False

Here, message == "" checks for empty string and after "or" it checks for first and last letter of word.

Answer 9

Just to make it more readable since you are learning and haven't used "if not"

def first_and_last(message):
    if message == "":
        return True
    elif message[0] == message[-1]:
        return True  
    else:
        return False

print(first_and_last("else"))
print(first_and_last("tree"))
print(first_and_last(""))

output would be  below 

True
False
True

Answer 10

def first_and_last(message):
    if message == "" or message[0] == message[-1]:
        return True
    else:
        return False

print(first_and_last("else"))
print(first_and_last("tree"))`enter code here`
print(first_and_last(""))

Answer 11

# could it work like this as well? if not why? thanks :)
def first_and_last(message):
while bool(message) == True:
    first_letter = str(message[0])
    last_letter = str(message[-1])
    if first_letter == last_letter:
        return True
    else :
        return False
 return True

 print(first_and_last("else"))
 print(first_and_last("tree"))
 print(first_and_last(""))
 # Output (True, False, True)