Use one list as search key for another list with sublist of list

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Hello,
I have two lists that returns some vector values with it's own name:

Python

list1 = [['orange', [1, 2, 3]]]
list2 = [['apple', [1, 2, 3]], ['banana', [1, 2, 3]], ['pear', [-1, 2, 3]], ['kiwi', [1, -2, 3]]]

So far I have a code that uses the list1 as a "search key" and ignoring the string on the list2 and print out the sublist that are not the same than in list1, which gives this result:
[['pear' [-1, 2, 3], ['kiwi', [-1, -2, 3]]]

This is the script:
<pre><pre lang="Python">S = set(tuple(x[1]) for x in list1)
result = [x for x in list2 if tuple(x[1]) not in S]

The current code I have working returns the correct result by ignoring the strign, but I would like to go futher and compare only the first value of the vector list, which the result should be:
[['pear' [-1, 2, 3]] only eventhough kiwi has different value but in the second item of the vector list.

What I have tried:

S = set(tuple(x[1]) for x in list1[0])
result = [x for x in list2[0] if tuple(x[1]) not in S]

but it gives a TypeError since is a tuple and not strings

Posted 10-Jan-22 23:23pm

Juan Carlos Felipe

Updated 11-Jan-22 1:09am

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2 solutions

Solution 2

I found the answer thanks to the help over other site, I want to share it here just in case anyone else need it.

list1 = [['orange', [1, 2, 3]]]
list2 = [['apple', [1, 2, 3]], ['banana', [1, 2, 3]], ['pear', [-1, 2, 3]], ['kiwi', [1, -2, 3]]]

y = [x for x in list2 if x[1][0] not in [a[1][0] for a in list1]]
print(y)

Posted 11-Jan-22 1:09am

Juan Carlos Felipe

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Richard MacCutchan · Accepted Answer · 2022-01-11T00:55:00

Solution 1

I think your code is over complicated. try the following:

Python

list1 = [['orange', [1, 2, 3]]]
list2 = [['apple', [1, 2, 3]], ['banana', [1, 2, 3]], ['pear', [-1, 2, 3]], ['kiwi', [1, -2, 3]]]
S = [x[1] for x in list1]
print('search list:', S)
# result = [x[0] for x in list2 if x[1] not in S]
result = [x[0] for x in list2 if x[1][0] != S[0][0]]
print('result', result)

However, I am not totally clear what result you are trying to obtain.

Posted 11-Jan-22 0:55am

Richard MacCutchan

Updated 11-Jan-22 1:14am

v2

Comments

Juan Carlos Felipe 11-Jan-22 7:00am

Thank you for your answer, the desired result I'm looking after is returning only ['pear', [-1, 2, 3], since is the only item that in the index[0] of its list is different than the list1 index[0].
I hope this makes sense.

Richard MacCutchan 11-Jan-22 7:14am

See my updated code. I have left the original line as a comment for comparison.

Juan Carlos Felipe 11-Jan-22 8:17am

That's great, thank you, the only missing thing it should be to print the whole item list ['pear', [-1, 2, 3]]. Is it possible with your solution?

Richard MacCutchan 11-Jan-22 8:37am

Yes, you can print any part, or all, of the element(s). Try

result = [x for x in list2 if x[1][0] != S[0][0]]

Juan Carlos Felipe 11-Jan-22 8:40am

Fantastic, really appreciate your time and knowledge. Thank you :)

Richard MacCutchan 11-Jan-22 8:44am

You are welcome.