slice
We saw how to access individual characters of a string with
[]. It’s also possible to select a specific slice of a string - take several consecutive characters. This can be accomplished with the same [] brackets but by providing two numbers - the start and the end of the selection:s = 'This is a long long string'
print(s[0: 1]) # T
print(s[0: 2]) # Th
print(s[0: 18]) # This is a long lon
print(s[1: 3]) # hi
print(s[1: -1]) # his is a long long strin
print(s[3: -2]) # s is a long long stri
print(s[-10: -2]) # ong striNote 1: The start is always inclusive and the end is always exclusive ⇒
[start; end).Note 2: Both start and end can be negative - implying negative indexing.
Challenge
We should like to know what’s the central segment of a string.
Given a string of length
n, we would like to see the letters that span the positions from n/4 to 3n/4. The input contains a single line of text, which is guaranteed to have a length divisible by 4.
The program should print the central segment.
Input | Output |
abcd | bc |
abcdefgh | cdef |
Constraints
Time limit: 2 seconds
Memory limit: 512 MB
Output limit: 1 MB