Timeline for GatherBy based on condition imposed on index variable
Current License: CC BY-SA 3.0
15 events
| when toggle format | what | by | license | comment | |
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| Feb 5, 2015 at 21:04 | comment | added | Basheer Algohi | @Mr.Wizard thanks for the up voting and for the new thinks I learned about ## :-), ^_ _ | |
| Feb 5, 2015 at 13:45 | comment | added | Mr.Wizard |
By the way this can be written Cases[testdat, {# | ##2, __}] & @@@ {{1, 2}, {3, 4, 5}, {6}} if you like that sort of weirdness. :^)
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| Feb 5, 2015 at 13:43 | comment | added | Mr.Wizard | @Algohi It's not really bad however with the example given (only three groups) so +1 for a clean method nevertheless. | |
| Feb 5, 2015 at 13:27 | comment | added | Basheer Algohi | @Mr.Wizard I Agree. The input list is scanned once for each group. | |
| Feb 5, 2015 at 13:12 | comment | added | Mr.Wizard | This code is less than optimal because the input list will be scanned once for each group. | |
| Dec 12, 2014 at 3:55 | comment | added | ramesh | Let us continue this discussion in chat. | |
| Dec 11, 2014 at 19:58 | comment | added | Basheer Algohi | does this resemble your problem? Cases[RandomInteger[20, {200, 3}], {Alternatives[##], __}] & @@@ Partition[Range[20], 3] | |
| Dec 11, 2014 at 16:55 | comment | added | ramesh | I did try this but I get all blanks. Let me work more on it and get back to you. | |
| Dec 11, 2014 at 16:38 | comment | added | Basheer Algohi | you mean newindex=Partition[oldindex, 3]? use index instead of {index} in my code. like this: Cases[testdat, {Alternatives[##], __}] & @@@newindex | |
| Dec 11, 2014 at 16:06 | comment | added | ramesh | @ Algohi, thanks for your update. I think, this might serve my need. I am working on it thought on my real data set. | |
| Dec 11, 2014 at 15:53 | history | edited | Basheer Algohi | CC BY-SA 3.0 |
added 296 characters in body
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| Dec 11, 2014 at 15:37 | comment | added | ramesh | In your code, you have {{1, 2}, {3, 4, 5}, {6}} as criterion. Can we specify criteria as function than list? Like index is between two numbers: i<=index<=i+1, {i, 1, 6, 2}. Something like this. | |
| Dec 11, 2014 at 15:24 | comment | added | Basheer Algohi | if you have too big data then cases is your choose because it is fast. i don't get what you mean be index is too big to navigate? as long as you have the criteria to group the rows then you can use this method. | |
| Dec 11, 2014 at 15:21 | comment | added | ramesh | @ Algohi, thank you for your answer. What if I have a large data and index is too big to navigate. In fact, I have over 2M obs. | |
| Dec 11, 2014 at 15:15 | history | answered | Basheer Algohi | CC BY-SA 3.0 |