Timeline for Find the length of the intersection of two lists including duplicates
Current License: CC BY-SA 3.0
4 events
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| Apr 28, 2016 at 14:08 | comment | added | LLlAMnYP |
@JasonB Tally gives the number of occurrences of the elements of the combined lists A and B but preserves the order in which the elements appear. Therefore the first Length@listA elements of Tally[listA~Join~listB] will give how many times the elements of listB appear in listA plus one. This hinges on the fact that all elements of listA must be distinct, but is otherwise more general than my solution, which demands listA === Range@Length@listA
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| Apr 28, 2016 at 13:56 | comment | added | LLlAMnYP |
+1 for superior general solution. I'm very surprised, that Tally is so fast.
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| Apr 28, 2016 at 12:11 | comment | added | Jason B. | What is it doing, and why is it so much faster? | |
| Apr 28, 2016 at 11:38 | history | answered | ciao | CC BY-SA 3.0 |