CODEWITHSUNDEEP
pythonpython-2.7listfor-loop
Lily
Lily

Reputation: 65

Comparing items in lists within same indices python

I want to compare between 2 lists and extract the contents 

colours = ["yellow", "light pink", "red", "dark blue", "red"]

items = ["the sun is yellow but the sunset is red ",
         "the pink cup is pretty under the light", 
         "it seems like the flower is red", 
         "skies are blue",
         "i like red"]

Expected result:

["yellow", "pink light", "red", "blue", "red"]

If there are two words in the colours list, the item will be broken down into two words. As you can see, the order of the words in colours ("pink", "light") is not important as the two words are broken into individual words and then compared individually in the sentences. Note that in the first item in items, although there is "red" in the colours list, I do not want to extract it because the "red" is in different index from the item's index.

for the 4th index which are "dark blue" and "skies are blue", the result should display only "blue" because dark is not present in the items.

I've tried to code but the results that I get is the lists are not compared within same indices by once, instead it loops through many times, hence the repeated "red". 

colours=["yellow","light pink","red"," dark blue","red"]

items=["the sun is yellow but the sunset is red ","the pink cup is pretty under the light", "it seems like the flower is red", "skies are blue","i like red"]

for i in colours:

y=i.split() #split 2 words to 1 word
    for j in y:
    #iterate word by word in colours that have more than 1 word
        for z in items: 
            s=z.split() #split sentences into tokens/words
            for l in s:
            #compare each word in items with each word in colours
                if j == l:
                    print j

Result:

yellow
light
pink
red
red
red
blue
red
red
red

Correct Result:

yellow
pink light 
red
blue
red

Upvotes: 1

Views: 62

Answers (3)

Alexander
Alexander

Reputation: 109526

Using sets to test for membership should be much faster, with a caveat:

>>> [' '.join(set(colour.split()) & set(item.split())) 
     for colour, item in zip(colours, items)]
['yellow', 'pink light', 'red', 'blue', 'red']

The caveat is that sets are unordered, so 'pink light' could come out as 'light pink'.

Upvotes: 1

blhsing
blhsing

Reputation: 106465

You can use the following list comprehension:

print([' '.join(w for w in i.split() if w in c.split()) for c, i in zip(colours, items)])

This outputs:

['yellow', 'pink light', 'red', 'blue', 'red']

Upvotes: 3

Austin
Austin

Reputation: 26039

With zip, you could do much easier:

colours=["yellow","light pink","red"," dark blue","red"]

items=["the sun is yellow but the sunset is red ","the pink cup is pretty under the light", "it seems like the flower is red", "skies are blue","i like red"]

lst = []
for x, y in zip(colours, items):
    word = ''
    for c in y.split():
        if c in x:
            word = word + ' ' + c
    lst.append(word.strip())

print(lst)
# ['yellow', 'pink light', 'red', 'blue', 'red']

Upvotes: 4

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