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I have the following dataframe df which was generated with an aggregate call by TERR on a larger dataframe that preformed two functions on a column. So in this case the mean and standard error were calculated on PC1 and PC2. The problem is that I need to now call up these values separately. If I try

df$PC1.mn it returns NULL however with df$PC1 I get a list of both. I need these matrices to be separate columns. Is there any way to achieve this?

EDIT: apart from the first column,each column is a matrix of 2 columns which need to be expanded into separate columns.

 TERR PC1.mn PC1.sem PC2.mn PC2.sem 1 MENS_10 0.82030703 0.05964201 0.60991007 0.03922947 2 MENS_14 0.22284209 0.07027761 0.01079179 0.03857742

output of str(df$PC1)

num [1:19, 1:2] 0.82 0.223 1.094 1.04 0.812 ... - attr(*, "dimnames")=List of 2 ..$ : NULL ..$ : chr [1:2] "mn" "sem"

output of dput(df)

structure(list(TERR = structure(1:19, .Label = c("MENS_10", "MENS_14", "MENS_16", "MENS_18", "MENS_2 ", "MENS_20", "MENS_24", "MENS_25", "MENS_26", "MENS_29", "MENS_31", "MENS_32", "MENS_40", "MENS_42", "MENS_44", "MENS_46", "MENS_5", "MENS_8", "MENS_E"), class = "factor"), PC1 = structure(c(0.820307033727786, 0.222842088186464, 1.09398346334857, 1.03987566591133, 0.811508841644094, 1.24651570248768, 1.05238710884733, 0.843375523572735, 0.685570397342129, 1.09996139295587, 1.1151090622921, -0.298832473495758, 1.29946851248417, 0.946576117066279, 0.187808783643163, 0.893302196795568, 0.983720713568758, 0.886156614045068, 1.25822951068011, 0.0596420103795457, 0.0702776122855427, 0.0404015364189346, 0.0447926762952018, 0.036140124264161, 0.0160560001285343, 0.0231077996353513, 0.0454453863107384, 0.0732883733170798, 0.0419403787520002, 0.0529142110353097, 0.113250160103334, 0.0317033323860567, 0.0499866649881185, 0.131566191776678, 0.0726248148670481, 0.0468352242077059, 0.0252178951026526, 0.0201191567959382 ), .Dim = c(19L, 2L), .Dimnames = list(NULL, c("mn", "sem" ))), PC2 = structure(c(0.609910070963486, 0.010791790442562, -0.019036172787209, 0.414690046178149, 0.386429802848653, 0.743955055344087, 0.906095700713572, 0.881751910465456, 0.393712721920078, 0.945199289980582, 0.778368954953892, 0.563653938290256, -0.225664575518917, 0.752018591494644, 0.0721395199667787, -0.948596863396142, 0.943337613028796, -0.107366982269548, -0.65976401574119, 0.039229472726257, 0.0385774221025136, 0.4269694476559, 0.0679840394899709, 0.041880478016631, 0.0143178196405501, 0.00951587961886708, 0.0196930171913273, 0.0984619155288124, 0.0079466733534216, 0.055388457985743, 0.0349441555633137, 0.214629105591149, 0.0636257142218683, 0.0888801495049588, 0.183337779507489, 0.010175333454896, 0.0628768381904623, 0.0795386419888819 ), .Dim = c(19L, 2L), .Dimnames = list(NULL, c("mn", "sem" ))), PC3 = structure(c(-0.326302104622856, -0.257388824025022, -0.717982657985263, -0.657589966361892, -0.321736105982529, 0.410407200147062, -0.78002620224271, -0.692036731761886, -0.0760579971344166, -0.593241418680366, 0.360266620210402, -0.573274417731803, -0.197552757548519, 0.588238516866691, -0.701976918873246, -0.0971384417779599, -0.360250102628055, -0.0799437535436827, 0.400789302478491, 0.070699100114383, 0.0169569534700048, 0.00318869179967574, 0.0560397912451556, 0.0714868684576213, 0.0184154105360385, 0.0231515714580647, 0.0446593876491272, 0.0728436000061978, 0.0617518825334356, 0.100569655433215, 0.0559660127669167, 0.049985590357157, 0.102855069056182, 0.0655873698867967, 0.0507424531437847, 0.0706588044346223, 0.029594746707871, 0.0259242551078958 ), .Dim = c(19L, 2L), .Dimnames = list(NULL, c("mn", "sem" ))), PC1_REF = structure(c(-1.79014822762748, -2.19654556764402, -0.706670680491541, 0.84222997068149, -0.200035213817825, 0.76159457082468, -2.96784934132109, -2.36363634780223, -1.6779292791128, -1.28863092729594, -1.71270440574731, -0.749560834674291, 1.22805142927275, -2.49193710281539, -3.51171040879644, -0.0312246304760417, -2.42278943771601, -2.58615357515189, 1.09617164069407, 0.121525527234789, 0.0627107120532972, 0.65184784602933, 0.0163433239917639, 0.0858171773639523, 0.0218127160037072, 0.198432324587447, 0.087394617281051, 0.0343381088419686, 0.151994945838798, 0.115252644765557, 0.0347868846563838, 0.0923561659189044, 0.209773659527996, 0.125483611165188, 0.164512129616854, 0.238097033334626, 0.115420144119389, 0.017684863965389), .Dim = c(19L, 2L), .Dimnames = list(NULL, c("mn", "sem"))), PC2_REF = structure(c(0.0191314514849518, 0.0379648844721645, -0.454797258156674, -0.316881255342318, -0.222640182135541, 0.398810588895599, 0.065801297918062, 0.163708550103078, 0.360407839286103, 0.487240920556612, 0.0595015980154598, 0.657245803004009, -0.0516881124702257, -1.40480795448723, 0.352986631679451, 0.36070244532732, -0.359172025543314, -1.22953037087422, -2.15254915446959, 0.0492863335469464, 0.024079577386548, 0.310968952096746, 0.0976750590235698, 0.0558342658138735, 0.0262868860364361, 0.0255728783826103, 0.0275967588543879, 0.0348972306236099, 0.0584917554768032, 0.0612924232752413, 0.019086945976421, 0.193539766002865, 0.189392084648141, 0.0311901287757335, 0.0446153794854082, 0.0566124654632608, 0.114494991588691, 0.109907100018088), .Dim = c(19L, 2L), .Dimnames = list(NULL, c("mn", "sem"))), PC3_REF = structure(c(-0.785662558526182, -0.477272546063659, -1.00517995097847, -1.02030113940379, 1.24398872718819, 0.607291320538, -1.46190383080967, -1.28148551680627, -0.507632811627629, -0.347706128537224, 0.0289620787098363, -0.052999165429303, -0.029647814698048, 1.17566638493985, -0.341007156514732, -0.80350511213881, -0.448713106410453, 1.9067734261776, 0.355448489072199, 0.0680129554696798, 0.0452539888036221, 0.107604471353131, 0.0205028642828262, 0.0544948584039173, 0.0157416677586763, 0.0880077236071284, 0.0647519131064312, 0.112523230074974, 0.116200699969251, 0.131793809035836, 0.0375505290549086, 0.124128738801318, 0.147075456084009, 0.106671365313098, 0.0597926204825535, 0.10691526418452, 0.0582383571872046, 0.0223774590546338), .Dim = c(19L, 2L ), .Dimnames = list(NULL, c("mn", "sem")))), .Names = c("TERR", "PC1", "PC2", "PC3", "PC1_REF", "PC2_REF", "PC3_REF"), row.names = c(NA, -19L), class = "data.frame")
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  • df$PC[,1] and df$PC[,2] both return NULL. Commented Jul 13, 2014 at 13:28
  • maybe df$PC1[[1]] and df$PC1[[2]] ? You really should provide something like str(df$PC1) or str(df) Commented Jul 13, 2014 at 13:30
  • still get NULL. Added output of str(df$PC1) Commented Jul 13, 2014 at 13:39
  • OK, added. Please note that the actual dataframe contains more columns than what I communicated in my question. I was trying to simplify for the original question. Commented Jul 13, 2014 at 13:46
  • 1
    @digEmAll It's reasonably simple to embed matrices as components of a dara frame. IIRC, I() allows one way to do this... Commented Jul 13, 2014 at 14:05

1 Answer 1

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df is a data.frame with 7 columns such that except for the first column each column is a matrix of 2 columns:

> str(df) 'data.frame': 19 obs. of 7 variables: $ TERR : Factor w/ 19 levels "MENS_10","MENS_14",..: 1 2 3 4 5 6 7 8 9 10 ... $ PC1 : num [1:19, 1:2] 0.82 0.223 1.094 1.04 0.812 ... ..- attr(*, "dimnames")=List of 2 .. ..$ : NULL .. ..$ : chr "mn" "sem" $ PC2 : num [1:19, 1:2] 0.6099 0.0108 -0.019 0.4147 0.3864 ... ..- attr(*, "dimnames")=List of 2 .. ..$ : NULL .. ..$ : chr "mn" "sem" $ PC3 : num [1:19, 1:2] -0.326 -0.257 -0.718 -0.658 -0.322 ... ..- attr(*, "dimnames")=List of 2 .. ..$ : NULL .. ..$ : chr "mn" "sem" $ PC1_REF: num [1:19, 1:2] -1.79 -2.197 -0.707 0.842 -0.2 ... ..- attr(*, "dimnames")=List of 2 .. ..$ : NULL .. ..$ : chr "mn" "sem" $ PC2_REF: num [1:19, 1:2] 0.0191 0.038 -0.4548 -0.3169 -0.2226 ... ..- attr(*, "dimnames")=List of 2 .. ..$ : NULL .. ..$ : chr "mn" "sem" $ PC3_REF: num [1:19, 1:2] -0.786 -0.477 -1.005 -1.02 1.244 ... ..- attr(*, "dimnames")=List of 2 .. ..$ : NULL .. ..$ : chr "mn" "sem"

Thus df$PC1 is the first matrix, df$PC1[, 1] or dfPC1[, "mn"] is the first column of the PC1 matrix and df$PC1[, 2] or df$PC1[, "sem"] is the second column of the PC1 matrix, etc.

This converts df to a flat data frame of 13 columns:

do.call(data.frame, df)
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Thanks for the concise answer. I will update my question to reflect correct terminology.

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