Chr*_*ris 2 r reshape2 dplyr data.table tidyr
我需要在不使用的情况下转置数据帧，t()因为我想避免将其转换为矩阵。所以，我正在使用这里的解决方案：
mydata <- data.table(col0=c("row1","row2","row3"),
col1=c(11,21,31),
col2=c(12,22,32),
col3=c(13,23,33))
mydata
# col0 col1 col2 col3
# row1 11 12 13
# row2 21 22 23
# row3 31 32 33
dcast(melt(mydata, id.vars = "col0"), variable ~ col0)
# variable row1 row2 row3
# 1: col1 11 21 31
# 2: col2 12 22 32
# 3: col3 13 23 33
我对我正在使用的数据使用相同的逻辑：
x <- merge(as.data.frame(table(mtcars$mpg)), as.data.frame(round(prop.table(table(mtcars$mpg)),2)), by="Var1", all.x=TRUE)
data.table::dcast(data.table::melt(x, id.vars = "Var1"), variable ~ Var1)
有用！但它给了我一个警告和一个“未来的错误”：
Run Code Online (Sandbox Code Playgroud)Warning message in data.table::melt(x, id.vars = "Var1"): “The melt generic in data.table has been passed a data.frame and will attempt to redirect to the relevant reshape2 method; please note that reshape2 is deprecated, and this redirection is now deprecated as well. To continue using melt methods from reshape2 while both libraries are attached, e.g. melt.list, you can prepend the namespace like reshape2::melt(x). In the next version, this warning will become an error.” Warning message in data.table::dcast(data.table::melt(x, id.vars = "Var1"), variable ~ : “The dcast generic in data.table has been passed a data.frame and will attempt to redirect to the reshape2::dcast; please note that reshape2 is deprecated, and this redirection is now deprecated as well. Please do this redirection yourself like reshape2::dcast(data.table::melt(x, id.vars = "Var1")). In the next version, this warning will become an error.”
另外，我一直在试图使用转的解决方案，从数据帧在这里使用dplyr::spread()，但它似乎是远远超过从溶液中复杂的data.table包（当值的列都超过1，在这种情况下）。我更习惯了dplyr()，tidyverse()但data.table解决方案要简单得多，忽略它。
附加信息。
> sessionInfo()
R version 3.6.0 (2019-04-26)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Debian GNU/Linux 9 (stretch)
Matrix products: default
BLAS/LAPACK: /usr/lib/libopenblasp-r0.2.19.so
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=C
[7] LC_PAPER=en_US.UTF-8 LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] GGally_1.4.0 forcats_0.4.0 stringr_1.4.0 dplyr_0.8.3
[5] purrr_0.3.2 readr_1.3.1 tidyr_1.0.0 tibble_2.1.3
[9] ggplot2_3.2.1.9000 tidyverse_1.2.1 bigrquery_1.2.0 httr_1.4.1
loaded via a namespace (and not attached):
[1] bit64_0.9-7 jsonlite_1.6 splines_3.6.0
[4] modelr_0.1.4 Formula_1.2-3 assertthat_0.2.1
[7] getPass_0.2-2 latticeExtra_0.6-28 cellranger_1.1.0
[10] pillar_1.4.2 backports_1.1.5 lattice_0.20-38
[13] glue_1.3.1 uuid_0.1-2 digest_0.6.21
[16] checkmate_1.9.4 RColorBrewer_1.1-2 rvest_0.3.4
[19] colorspace_1.4-1 htmltools_0.4.0 Matrix_1.2-17
[22] plyr_1.8.4 psych_1.8.12 pkgconfig_2.0.3
[25] broom_0.5.2 haven_2.1.1 scales_1.0.0
[28] htmlTable_1.13.2 generics_0.0.2 withr_2.1.2
[31] repr_1.0.1.9000 skimr_1.0.7 nnet_7.3-12
[34] cli_1.1.0 mnormt_1.5-5 survival_2.44-1.1
[37] magrittr_1.5 crayon_1.3.4 readxl_1.3.1
[40] evaluate_0.14 fs_1.3.1 nlme_3.1-141
[43] xml2_1.2.2 foreign_0.8-72 data.table_1.12.4
[46] tools_3.6.0 hms_0.5.1 gargle_0.4.0
[49] lifecycle_0.1.0 munsell_0.5.0 cluster_2.1.0
[52] compiler_3.6.0 rlang_0.4.0 grid_3.6.0
[55] pbdZMQ_0.3-3 IRkernel_1.0.2.9000 rstudioapi_0.10
[58] htmlwidgets_1.5.1 base64enc_0.1-3 gtable_0.3.0
[61] DBI_1.0.0 reshape_0.8.8 reshape2_1.4.3
[64] R6_2.4.0 gridExtra_2.3 lubridate_1.7.4
[67] knitr_1.25 bit_1.1-14 zeallot_0.1.0
[70] Hmisc_4.2-0 stringi_1.4.3 parallel_3.6.0
[73] IRdisplay_0.7.0.9000 Rcpp_1.0.2 vctrs_0.2.0
[76] rpart_4.1-15 acepack_1.4.1 xfun_0.10
[79] tidyselect_0.2.5
我需要在不使用 t() 的情况下转置数据帧，因为我想避免将其转换为矩阵。
如果您唯一的要求是避免将数据框强制转换为矩阵，则可以使用data.table::transposewhich requires version >= 1.12.4
data.table::transpose(
mydata,
keep.names = 'variable',
make.names = names(mydata)[1])
# variable row1 row2 row3
# 1: col1 11 21 31
# 2: col2 12 22 32
# 3: col3 13 23 33