Can any one please explain me why this prints none for the first statement where it says "university"? The second command prints index(-5) and index(3) which is cd but the first one gives me back nothing.
x = "university"
print(x[-5:4])
x = "abcdefg"
print(x[-5:4])
You print out slices of strings which start at index -5 and end at index 4. Slicing differs from single-element access (x[i]) not only in one or more colons (:) being involved, but in so far as you specify a range with a start index and an end index (start is inclusive whereas end isn't). The range [-5:4] is empty for "university" and contains two elements for "abcdefg".
See for illustration the content of the strings in relation to indices:
0 1 2 3 ]4
u n i v e r s i t y
[-5 -4 -3 -2 -1
0 1 2 3 ]4
a b c d e f g
[-5 -4 -3 -2 -1
... which make it obvious that that the substring for university must be empty.
What you, probably, might be expecting is a 4-character substring beginning at index -5 which can be achieved by x[-5,-1].
In the string "university" the index -5 is 'e' but index 4 is 'r'.
If you print the values
x = "university"
print(x[-5:])
print(x[:4])
You get
rsity
univ
It's because the indexes aren't on the letters, but between the letters. so you get "unive||rsity" with | being an index.
In print(x[-5:4]) function, the first index -5 indicate "r" and second index 4 indicate "e" so first index was greater than the second index at the position of string.
However, in case of x= "university", the starting index are larger in position, so there is no overlapping section, so no value is output.
If you fix it with print(x[-9:4]) it will out put 'niv'.
I hope that it will help you.
thanks
