I am studying slicing in strings using the slicing operator :.
The string I have chosen is word = 'fabricated'.
According to me, the output for the below statements:
print(word[5:-8])
print(word[-3:-9])
should be:
cir
tacirb
However, nothing is getting printed on running these statements. Neither on Google Colab nor on VS Code.
But when I specifically mention the step parameter as follows:
print(word[5:-8:-1])
print(word[-3:-9:-1])
I get my expected output as:
cir
tacirb
I would like to understand why I am getting a string of length 0 although the step parameter is not mandatory.
As you note, the step size is not mandatory, but it defaults to None. In particular, word[5:-8] is equivalent to word[slice(5, -8)] or word[slice(5, -8, None)].
When word.__getitem__ gets such a slice, it treats None the same as 1. (I suspect most __getitem__ implementations would, but they don't need to.) When the step size is positive, you only get a non-empty string if start < stop, regardless of the signs involved. When the step size is negative (i.e., when a negative step is explicitly provided), then a non-empty string is produced if stop < start (again, independent of the signs involved).