String Slice-athon

This challenge has five miniature exercises to help practice proficiency in string slicing. Check the examples below for a visual indicator of how to slice the strings. Good luck!

Examples

txt = "abcdefghijklmnopqrstuvwxyz"

challenge1(txt) ➞ "abcde"
# First 5 characters of the string.

challenge2(txt) ➞ "vwxyz"
# Last 5 characters of the string.

challenge3(txt) ➞ "zyxwvutsrqponmlkjihgfedcba"
# All characters in the string from back.

challenge4(txt) ➞ "fedcba"
# First 6 characters in the string (start with 6th character and go backwards).

challenge5(txt) ➞ "tvxz"
# Take last 7 characters and only return odd positioned ones.

Notes

• Check the Tests tab for more examples.
• You are not allowed to concatenate strings together! Results must be achieved purely through string slicing!