Opening text file, converting one four letter word to another

I am trying to open a saved text file that has a short sentence in it and then convert all four letter words in the sentence to "XXXX". Then save it back to the file. So far I am struggling with this. I pasted what I have done so far, but seem to be stuck now. I'm not sure what is wrong with what I have or if I am just missing something. Also I am new to the forum so if someone can tell me how to post my program properly, I will fix it. Any help would be greatly appreciated!



def censor():
filename = input("Enter name of file: ")
file = open(filename, 'r+')
i = 0
alist = []
for element in file:
words = element.split()
for i in range(len(words)):
if len(words[i]) == 4:
element.replace(words, "XXXX")
i = i+1
alist.append(newwords)
else:
alist.append(words)
print (alist)
file.close()
file1 = open(filename, 'w')
for element in alist:
file.write(alist)
file.close()

I'd write the program with flex.

I did not test your program. I'd guess that
1) you have trouble identifying 4 letter words. Your program would remove "cat." from "I ate my cat."
2) You have trouble reconstructing the original.

If I had to use python I'd use the regular expression package,
import re
With flex I'd also use regular expressions---it's so much easier.

Hi Ted,

I have done something similar with Python using regex. I have popped my code below.



To format your code snippets you just need to highlight the text and click the # button which will wrap you selection with [CODE] tags.

Quick note - building regex patterns can be rather daunting so I find it helpful to use a piece of open source software called Kodos which you can find http://kodos.sourceforge.net/.

I think this line is the problem:

element.replace(words, "XXXX")

Try changing that to:

element.replace(words[i], "XXXX")