So my problem is this, I have a file that looks like this:
[SHIFT]this isrd[BACKSPACE][BACKSPACE] an example file[SHIFT]1
This would of course translate to
' This is an example file!'
I am looking for a way to parse the original content into the end content, so that a [BACKSPACE] will delete the last character(spaces included) and multiple backspaces will delete multiple characters. The [SHIFT] doesnt really matter as much to me. Thanks for all the help!
Here's one way, but it feels hackish. There's probably a better way.
def process_backspaces(input, token='[BACKSPACE]'):
"""Delete character before an occurence of "token" in a string."""
output = ''
for item in (input+' ').split(token):
output += item
output = output[:-1]
return output
def process_shifts(input, token='[SHIFT]'):
"""Replace characters after an occurence of "token" with their uppecase
equivalent. (Doesn't turn "1" into "!" or "2" into "@", however!)."""
output = ''
for item in (' '+input).split(token):
output += item[0].upper() + item[1:]
return output
test_string = '[SHIFT]this isrd[BACKSPACE][BACKSPACE] an example file[SHIFT]1'
print process_backspaces(process_shifts(test_string))
If you don't care about the shifts, just strip them, load
(defun apply-bspace ()
(interactive)
(let ((result (search-forward "[BACKSPACE]")))
(backward-delete-char 12)
(when result (apply-bspace))))
and hit M-x apply-bspace while viewing your file. It's Elisp, not python, but it fits your initial requirement of "something I can download for free to a PC".
Edit: Shift is trickier if you want to apply it to numbers too (so that [SHIFT]2 => @, [SHIFT]3 => #, etc). The naive way that works on letters is
(defun apply-shift ()
(interactive)
(let ((result (search-forward "[SHIFT]")))
(backward-delete-char 7)
(upcase-region (point) (+ 1 (point)))
(when result (apply-shift))))
This does exactly what you want:
def shift(s):
LOWER = '`1234567890-=[];\'\,./'
UPPER = '~!@#$%^&*()_+{}:"|<>?'
if s.isalpha():
return s.upper()
else:
return UPPER[LOWER.index(s)]
def parse(input):
input = input.split("[BACKSPACE]")
answer = ''
i = 0
while i<len(input):
s = input[i]
if not s:
pass
elif i+1<len(input) and not input[i+1]:
s = s[:-1]
else:
answer += s
i += 1
continue
answer += s[:-1]
i += 1
return ''.join(shift(i[0])+i[1:] for i in answer.split("[SHIFT]") if i)
>>> print parse("[SHIFT]this isrd[BACKSPACE][BACKSPACE] an example file[SHIFT]1")
>>> This is an example file!
It seems that you could use a regular expression to search for (something)[BACKSPACE] and replace it with nothing...
re.sub('.?\[BACKSPACE\]', '', YourString.replace('[SHIFT]', ''))
Not sure what you meant by "multiple spaces delete multiple characters".
You need to read the input, extract the tokens, recognize them, and give a meaning to them.
This is how I would do it:
# -*- coding: utf-8 -*-
import re
upper_value = {
1: '!', 2:'"',
}
tokenizer = re.compile(r'(\[.*?\]|.)')
origin = "[SHIFT]this isrd[BACKSPACE][BACKSPACE] an example file[SHIFT]1"
result = ""
shift = False
for token in tokenizer.findall(origin):
if not token.startswith("["):
if(shift):
shift = False
try:
token = upper_value[int(token)]
except ValueError:
token = token.upper()
result = result + token
else:
if(token == "[SHIFT]"):
shift = True
elif(token == "[BACKSPACE]"):
result = result[0:-1]
It's not the fastest, neither the elegant solution, but I think it's a good start.
Hope it helps :-)
