[R-sig-eco] LEVELS function NULL

[Thierry Onkelinx]

Notice that the levels are ordered alphabetically. Use factor() and it
level argument to get them in a more sensible order.

Best regards,

ir. Thierry Onkelinx
Statisticus / Statistician

Vlaamse Overheid / Government of Flanders
INSTITUUT VOOR NATUUR- EN BOSONDERZOEK / RESEARCH INSTITUTE FOR NATURE AND
FOREST
Team Biometrie & Kwaliteitszorg / Team Biometrics & Quality Assurance
thierry.onkelinx using inbo.be
Havenlaan 88 bus 73, 1000 Brussel
www.inbo.be

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Op di 23 jun. 2020 om 18:12 schreef Vesna Gulin <vesna.gulin using biol.pmf.hr>:

> Hi,
>
>
>
> Thank you! It was indeed a character :) I used
>
> my_data$Sampling <- as.factor(my_data$Sampling)
>
> and now it works:
>
>
>
> > levels(my_data$Sampling)
>
> [1] "Dec17" "Jan18" "Jun18" "Mar18" "May18" "Nov18" "Oct17" "Sep18"
>
>
>
> Kr,
>
> Vesna
>
>
>
>
>
>
>
> From: Torsten Hauffe <torsten.hauffe using gmail.com>
> Sent: Tuesday, June 23, 2020 6:06 PM
> To: Vesna Gulin <vesna.gulin using biol.pmf.hr>
> Cc: r-sig-ecology using r-project.org
> Subject: Re: [R-sig-eco] LEVELS function NULL
>
>
>
> Hi,
>
>
>
> What is the output of
>
> class(my_data$Sampling)?
>
>
>
> If it is not factor (but character), you could write
>
> my_data$Sampling <- as.factor(my_data$Sampling)
>
>
>
> Then levels(my_data$Sampling) should return Sep18 etc.
>
>
>
> Cheers!
>
>
>
> On Tue, Jun 23, 2020 at 6:00 PM Vesna Gulin <vesna.gulin using biol.pmf.hr
> <mailto:vesna.gulin using biol.pmf.hr> > wrote:
>
> Hi everyone,
>
>
>
> It has been a couple months now of using R and I am slowly trying to switch
> from using Statistica to R in order to process my data (for PhD purposes).
>
>
>
> I did some basic statistics and now I would like to try Kruskal-Wallis
> (following this guideline:
>
> http://www.sthda.com/english/wiki/kruskal-wallis-test-in-r )
>
> but I have been stuck for days as I can't seem to find a reason why the
> levels function keeps giving me NULL.
>
>
>
> My data is a data frame:
>
>
>
> my_data
>
>    Temperature Sampling
>
> 1         9.90    Dec17
>
> 2        10.00    Dec17
>
> 3        10.00    Dec17
>
> 4        10.10    Dec17
>
> 5         9.90    Dec17
>
> 6        10.10    Dec17
>
> 7        10.20    Dec17
>
> 8        10.10    Jan18
>
> 9        10.50    Jan18
>
> 10       10.80    Jan18
>
> 11       10.30    Jan18
>
> 12       10.30    Jan18
>
> 13       10.20    Jan18
>
> 14       10.50    Jan18
>
> 15       20.90    Jun18
>
> 16       20.80    Jun18
>
> 17       20.50    Jun18
>
> 18       20.50    Jun18
>
> 19       20.70    Jun18
>
> 20       20.60    Jun18
>
> 21       20.50    Jun18
>
> 22       10.50    Mar18
>
> 23       11.40    Mar18
>
> 24       10.90    Mar18
>
> 25       10.60    Mar18
>
> 26       11.60    Mar18
>
> 27       11.20    Mar18
>
> 28       12.20    Mar18
>
> 29       19.40    May18
>
> 30       19.00    May18
>
> 31       20.80    May18
>
> 32       19.50    May18
>
> 33       18.60    May18
>
> 34       18.10    May18
>
> 35       19.20    May18
>
> 36       16.80    Nov18
>
> 37       16.50    Nov18
>
> 38       18.40    Nov18
>
> 39       18.10    Nov18
>
> 40       16.70    Nov18
>
> 41       16.70    Nov18
>
> 42       18.50    Nov18
>
> 43       15.50    Oct17
>
> 44       15.10    Oct17
>
> 45       15.00    Oct17
>
> 46       15.80    Oct17
>
> 47       15.20    Oct17
>
> 48       15.10    Oct17
>
> 49       15.20    Oct17
>
> 50       23.40    Sep18
>
> 51       24.05    Sep18
>
> 52       23.70    Sep18
>
> 53       23.40    Sep18
>
> 54       24.05    Sep18
>
> 55       23.80    Sep18
>
> 56       24.15    Sep18
>
>
>
> When I hit levels(my_data$Sampling) it gives me
> NULL
>
>
>
> I would very much appreciate any help.
>
>
>
> Kind regards,
>
> Vesna
>
>
>
>
>
>
>
> Vesna Gulin,  Research Assistant
>
>
>
> Department of Biology
>
>
>
> Faculty of Science
>
> University of Zagreb
>
>
>
> Rooseveltov trg 6, 10000 Zagreb, Croatia
>
>
>
>
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