Reshape data for values in one column

dataframe, melt, r, reshape

Solution

dcast from the reshape2 package does this:

require(reshape2)
dcast(data, test ~ ID , value_var = 'test_result' )

#  test  1  2  3  4  5
#1    A NA  9 11 NA NA
#2    B 10 NA NA NA NA
#3    C NA NA NA  7 NA
#4    F NA NA NA NA  5

Problem

My data.frame looks like this ``` ID | test | test_result 1 | B | 10 2 | A | 9 3 | A | 11 4 | C | 7 5 | F | 5 ``` And I want to get something like this: ``` test | test_reult_ID1 | test_result_ID2 | test_result_ID3 ... A | NA | 9 | 11 B | 10 | NA | NA ``` It works with reshape() to the wide format with only a few cases but with the whole data frame (about 23.000 ID´s) reshape () takes too long. Melt() and cast() do reshape the data but replace the values in test_result by the frequency of the test. Any other ideas how to manage this? Thanks!

Original source

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