 # FAQ: Modifying DataFrames - Reviewing Lambda Function

This community-built FAQ covers the “Reviewing Lambda Function” exercise from the lesson “Modifying DataFrames”.

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To pin point the last character, why not use x[-1] instead of x[len(x)-1]?

Are there situations where x[-1] will not work?

Thanks

``````mylambda = lambda x: x+x[-1]
print(mylambda('Hello World'))
``````

certainly produces the same results
Hd

I don’t know why they added the complicated
x[len(x)-1]

What would the two lines of code be if we wanted to print the first and last number of an integer instead of the first and last letter? I’ve not had any luck in coming up with the solution on my own.

I’m a bit late but something like this?

``````int_number = 398735

mylambda = lambda x: x[:1] + x[-1:]
print(int(mylambda(str(int_number))))
``````

If you don’t mind if you print an integer or a string you can get rid of the int().

The constraint put in the exercise " assuming the string is at least 2 characters long", shouldn’t be somehow written in the code? Maybe by using an if statement?

I tried to put a string one-character long, e.g. ‘H’ and the output is ‘HH’ ; a result which I think is not thorougly consistent with the way the exercise was expressed.

However, when I added … if len(x)>2 else ‘None’ and wrote again print(mylambda(‘H’)),
then the output was ‘None’.