Access Characters

Some scripts you will write for cybersecurity encryption and decryption will need to access each character in a string.   As a warmup for this, let's try a script that checks and displays a certain character in a string.

Example script: char_access_intro

  • Enter this script and save it as char_access_intro.  
  • Flash the script into the micro:bit.
# char_access_intro

from microbit import *


s = "ABCDEF 12345"
print("Fifth character in s:")
c = s[5]
print("c = s[5] =", c)
  • Open the terminal.
  • Verify that it displays c = s[5] = F.

  • Try replacing 5 with other values, like 0, 1, 2, ...and anything up to 11.  What happens with each value?

How char_access_intro Works

The string s is "ABCDEF 12345".  The string name, followed by a positive index value in square brackets, returns the character at that location in the string.  The index starts with A at s[0], B is at s[1], and so on up to the character 5 at s[11].  You can also use -1 through -12 to index characters from rightmost to left.