[Tutor] deleting elements out of a list.

[Alan Gauld]

On 15/06/2019 05:51, mhysnm1964 at gmail.com wrote:

Caveat: I'm picking this up late in the day and only had a cursory look
at it, so may be missing some critical insight...

> I have a list of x number of elements. Some of the elements are have similar
> words in them. For example:

Define "similar".
It implies not identical. What is different? What makes them
similar? Every time you introduce vague inequalities you imply
the need for some kind of intelligent function that removes
the ambiguity and vagueness. it  definitively says that these
two items are similar or not similar.

Can you write such a function? If so the problem should become
relatively simple.


> Dog food Pal
> Dog Food Pal qx1323 
> Cat food kitty
> Absolute cleaning inv123
> Absolute Domestic cleaning inv 222
> Absolute d 3333
> Fitness first 02/19
> Fitness first
> 
> I wish to remove duplicates. 

So what would the output look like if the above is the input?
My guess of what you want is:

qx1323
Cat kitty
Domestic
d 3333
02/19

Is that right?
Or is my idea of similar and duplicate different to yours?

> I could use the collection.Count method. This
> fails due to the strings are not unique, only some of the words are. 

Sorry, I can't understand that. It makes no sense to me.
You need to define strings and words in this context

> description = load_files() # returns a list

A list of what? characters, words, lines?

> for text in description:
>     words = text.split()
>     for i in enumerate(words):
>         Word = ' '.join(words[:i])

This is weird. enumerate returns tuples which you assign to i.
But then you use i in a slice opertion. But slice expects an
integer.


>         print (word)
>         answer = input('Keep word?')
>         if answer == 'n':
>             continue 
>         for i, v in enumerate(description):
>             if word in description[i]:
>                 description.pop[i]

Without any clue what the description data looks like we
can't really decipher what the code above does.

> description list will cause a error. If I copy the description list into a
> new list. And use the new list for the outer loop. I will receive multiple
> occurrences of the same text. 

I'm not sure thats true but it denends on what description looks like.

> 
> description = load_files() # returns a list
> 
> search_txt = description.copy() 
> 
> for text in search_txt:
>     words = text.split()
>     for i in enumerate(words):
>         Word = ' '.join(words[:i])
>         print (word)
>         answer = input('Keep word (ynq)?')
>         if answer == 'n':
>             continue 
>         elif answer = 'q':
>             break
> 
>         for i, v in enumerate(description):
>             if word in description[i]:
>                 description.pop[i]

The usual way to remove things from a list is to create a
new list using a filter

newlist = filter(test_function, oldlist)

or a list comprehension

newlist = [item for item in oldlist if test_function(item)]

Which brings us back to the beginning. Can you write a test
function that unambiguously defines what needs to be removed?


-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.amazon.com/author/alan_gauld
Follow my photo-blog on Flickr at:
http://www.flickr.com/photos/alangauldphotos