Timeline for How to merge two arrays in JavaScript and de-duplicate items
Current License: CC BY-SA 4.0
23 events
| when toggle format | what | by | license | comment | |
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| S Feb 24, 2023 at 23:11 | history | edited | Michael M. | CC BY-SA 4.0 |
Rescued links
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| S Feb 24, 2023 at 23:11 | history | suggested | tagurit | CC BY-SA 4.0 |
Rescued links
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| Feb 24, 2023 at 21:08 | review | Suggested edits | |||
| S Feb 24, 2023 at 23:11 | |||||
| S Jan 17, 2019 at 23:35 | history | suggested | Brak | CC BY-SA 4.0 |
This change corrects the "uniqueifying" behavior by populating initial assoc hash with the keys from the first array. It doesn't _appear_ to hurt the speed too much. I've also updated it to not use a falsy check for a speed boost, and not use booleans for a little additional speed bump.
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| Jan 17, 2019 at 19:44 | review | Suggested edits | |||
| S Jan 17, 2019 at 23:35 | |||||
| Jan 17, 2019 at 19:31 | comment | added | Brak | I took the liberty of updating the comprehensive jsperf page. I fixed whileLoopAlt2 by adding an initial population of the comparison hash, so now whileLoopAlt2 produces an array with only unique results; it's still pretty fast. Added new test differentiated by an undefined check rather than a falsy, for a faster whileLoopAlt3. And added an even faster(fastest) whileLoopAlt4 which uses null assignments rather than Booleans to save a tiny bit of speed. | |
| Jun 8, 2018 at 23:39 | comment | added | egiray | whileLoopAlt function does not removes all duplicates. | |
| Oct 18, 2017 at 6:36 | history | edited | Peter Mortensen | CC BY-SA 3.0 |
Active reading. Dressed the naked links.
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| May 23, 2017 at 12:18 | history | edited | URL Rewriter Bot |
replaced http://stackoverflow.com/ with https://stackoverflow.com/
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| Jun 5, 2015 at 0:24 | comment | added | Stephen S | @slickplaid Thanks for setting up the extended perf page. Unless I'm missing something, the "whileLoopAlt2" function doesn't work? It creates a new array containing the first array, and the second array (in reverse order). To avoid confusion I've made another revision that removes the broken function. I also added an additional example: jsperf.com/merge-two-arrays-keeping-only-unique-values/22 | |
| Apr 17, 2015 at 13:12 | history | edited | slickplaid | CC BY-SA 3.0 |
Removing last edit because code does not work properly. It does not satisfy the result of deduping the two arrays and combining them.
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| Apr 17, 2015 at 7:14 | comment | added | doldt | @slickpaid Thanks, good job on the extended perf page, very comprehensive! | |
| Apr 16, 2015 at 18:46 | history | edited | slickplaid | CC BY-SA 3.0 |
added one last test case
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| Apr 16, 2015 at 17:35 | history | edited | slickplaid | CC BY-SA 3.0 |
Added some qualifications to other answers. There are better answers in this list.
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| Apr 16, 2015 at 16:42 | comment | added | slickplaid | @doldt I've addressed your concerns in my answer and added a proper updated test to it as well. Let me know if you agree with those results or not. Also, I added another better result using an associative array. | |
| Apr 16, 2015 at 16:39 | history | edited | slickplaid | CC BY-SA 3.0 |
fixed issue with my original answer as one of the comments had pointed out. Added a second, faster result with the use of an associative array rather than indexOf on an basic array.
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| Apr 16, 2015 at 6:58 | comment | added | doldt | @slickplaid the linked tests are empty, and the next revision at jsperf hangs in the while loop. | |
| Apr 15, 2015 at 20:55 | comment | added | slickplaid | I agree with your premise @doldt, but disagree with your results. There is a fundamental design flaw with the loop based removal of entries, in that you have to recheck the length of the array after you have removed items, resulting in a slower execution time. A while loop working backwards does not have these effects. Here is an example with removing as many setup variables as I can without changing their original answer too much: jsperf.com/merge-two-arrays-keeping-only-unique-values/19 | |
| Apr 14, 2015 at 14:19 | comment | added | doldt | There's a flaw in your methodology: you put the creation of array3 into the setup phase, while that cost should only be part of your while-based solution's score. With this 1 line moved, your solution falls to the speed of the for loop based one. I understand that array can be reused, but maybe the other algorithms could benefit too from not having to declare and initialize every necessary building block. | |
| Feb 17, 2015 at 10:26 | review | Suggested edits | |||
| Feb 17, 2015 at 10:44 | |||||
| Sep 4, 2014 at 13:01 | history | edited | slickplaid | CC BY-SA 3.0 |
Missed defining some variables when copying it from my jsperf tests
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| Aug 4, 2014 at 14:19 | history | edited | slickplaid | CC BY-SA 3.0 |
added results
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| Aug 4, 2014 at 14:14 | history | answered | slickplaid | CC BY-SA 3.0 |