[R] About reshape dataset

[Daniel Nordlund]

On 10/22/2016 10:52 AM, lily li wrote:
> The code I'm using is:
> require(reshape)
> DF2 = melt(DF, id.vars = c('year', 'month', 'day'), measure.vars =
> c('site1_elev', 'site2_elev', 'site1_temp', 'site2_temp'))
>
> But it didn't work.
>
> On Sat, Oct 22, 2016 at 11:50 AM, lily li <chocold12 at gmail.com> wrote:
>
>> Hi R users,
>>
>> I want to melt a dataframe, but it mixed up the variables.
>>
>> DF is the original dataset:
>> year  month  day  site1_elev  site2_elev  site1_temp  site2_temp
>> 2000     5        6        1300          1500            20
>>  21
>> 2000     5        7        1300          1500            21              22
>> 2000     5        8        1300          1500            19              20
>> 2000     5        9        1300          1500            22              23
>>
>> How to melt the dataframe and get the following dataset? Thanks for your
>> help.
>>
>> year  month  day  siteID   elev   temp
>> 2000    5         6       1      1300    20
>> 2000    5         6       2      1500    21
>> 2000    5         7       1      1300    21
>> 2000    5         7       2      1500    22
>>
>>
>
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I am sure someone will come along with a "better" answer, but I played 
with this a bit and this is what I came up with. After running your code 
I ran

DF2$site <- substr(as.character(DF2$variable),1,5)
DF2$var <- substr(as.character(DF2$variable),7,10)
DF3 <- cast(DF2,year + month + day + site ~ var )


Hope this is helpful,

Dan

-- 
Daniel Nordlund
Port Townsend, WA  USA