Checking items in lists

Question

So wordlistdirty is a list of words which can contain some non-letter characters like commas in the end of the word. The script should delete those characters from each word if there are any and return just words. The problem is that if a word contains multiple of those, like 'bye).' script only deletes one non-letter. Also wordlistdirty contains  500 000 words, so i need to be very efficient and it seems to my code could be improved radically. How would you solve the task? Thanks a lot in advance!
python
ch_list = ["–", '–', '(', ')', ',', '.', '»', '«']
word_list = []
for word in word_list_dirty:
    word = list(word.lower())
    for letter in word:
        if letter in ch_list:
            word.remove(letter)
            print("".join(word))
    if word:
        word = "".join(word)
        word_list.append(word)

Print() is there only for debug, ideally in print() output all items should only contain letters

Dustin James · Accepted Answer

@olegovich7 (https://teamtreehouse.com/olegovich7),
I am a bit confused on a few parts of your question, but I'll try to help. I would make use of the built in features of .isalpha() found here: Python Docs (https://docs.python.org/3/library/stdtypes.html#str.isalnum)
I chose to wrap this into a function.
```python
def deletenonalpha(wordlist):
    alphaonlylist = []
for word in word_list:
    alpha_only = "".join(ch for ch in word if ch.isalpha())  # .isalpha() checks for alpha. Use .isalnum() to check for alpha numeric
    alpha_only_list.append(alpha_only)  # if you want all lower: alpha_only.lower()
return alpha_only_list

In the first part I am creating an empty list to store the new data. I am not sure if you are wanting to return the list back minus the non-alpha characters. The next thing I do is loop through each item in the word_list.
python
alphaonlylist = []  # if your end result is to not return a list then this is not needed

For each word I am iterating through each character and asking if it is an alpha character and if it is then I am joining it together to a temporary variable (temporary for each iteration of the word_list) and then appending it to the list created in step one.
python
for word in wordlist:
    alphaonly = "".join(ch for ch in word if ch.isalpha()) . #  pythonic way of writing this
    alphaonlylist.append(alphaonly)
```
I am then returning the list back after each word in wordlist has been iterated through.
python
return alpha_only_list

Let me know if I've caused more questions.
EDIT: Keep in mind this method will remove white space as well so the input should only be a list of just single words.

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olegovich7

olegovich7

Checking items in lists

1 Answer

Dustin James

Dustin James

Dustin James

Dustin James