Convert alphabet letters to number in Python

by

What about something like this:

print [ord(char) - 96 for char in raw_input('Write Text: ').lower()]

ord
list comprehension
ASCII character codes

EDIT
Since you asked me to explain I will… though it has been explained pretty well in the comments already by [?].

Let’s do this in more that one line to start.

input = raw_input('Write Text: ')
input = input.lower()
output = []
for character in input:
    number = ord(character) - 96
    output.append(number)
print output

This does the same thing, but is more readable. Make sure you can understand what is going on here before you try to understand my first answer. Everything here is pretty standard, simple Python. The one thing to note is the ord function. ord stand for ordinal, and pretty much every high level language will have this type of function available. It gives you a mapping to the numerical representation of any character. The inverse function of ord is called chr. 

chr(ord('x')) == 'x' # for any character, not just x.

If you test for yourself, the ordinal of a is 97 (the third link I posted above will show the complete ASCII character set.) Each lower case letter is in the range 97-122 (26 characters.) So, if you just subtract 96 from the ordinal of any lower case letter, you will get its position in the alphabet assuming you take ‘a’ == 1. So, ordinal of ‘b’ == 98, ‘c’ == 99, etc. When you subtract 96, ‘b’ == 2, ‘c’ == 3, etc.

The rest of the initial solution I posted is just some Python trickery you can learn called list comprehension. But, I wouldn’t focus on that as much as I would focus on learning to solve the problem in any language, where ord is your friend. I hope this helps.

More Related Contents:

  1. How to parse command line args in python [closed]
  2. How can I safely create a nested directory?
  3. Split / Explode a column of dictionaries into separate columns with pandas
  4. What’s the purpose of “send” function on Python generators?
  5. Binary search (bisection) in Python
  6. How to make smooth movement in pygame
  7. How to change the font size on a matplotlib plot
  8. How to construct a timedelta object from a simple string
  9. Way to change Google Chrome user agent in Selenium?
  10. plot different color for different categorical levels using matplotlib
  11. How to run an IPython magic from a script (or timing a Python script)
  12. Read from a log file as it’s being written using python
  13. Simulating Pointers in Python
  14. How do I write data into CSV format as string (not file)?
  15. TypeError: ‘list’ object is not callable while trying to access a list
  16. Using hyphen/dash in python repository name and package name
  17. pandas style background gradient both rows and columns
  18. How do you check for keyboard events with kivy?
  19. How can I know which exceptions might be thrown from a method call?
  20. os.walk without digging into directories below
  21. Read timeout using either urllib2 or any other http library
  22. Python selenium: DevTools listening on ws://127.0.0.1
  23. Tkinter example code for multiple windows, why won’t buttons load correctly?
  24. Compare XML snippets?
  25. Modify object in python multiprocessing
  26. How can I print bold text in Python?
  27. How to update yaml file using python
  28. python adds “E” to string
  29. Relative import error with py2exe
  30. Trigger an event when clipboard content changes

Leave a Comment