New to R, please guide !
Dataframe1 contain:
df1
Col1 Col2 Col3 Col4 Col5
A=5 C=1 E=5 F=4 G=2 --Row1
A=6 B=3 D=6 E=4 F=4 --Row2
B=2 C=3 D=3 E=3 F=7 --Row3
Dataframe2 contain one row with each parameters as field names: df2 = A B C D E F g .....'n'
Example Output (if values not found the null to be printed):
df2:
A B C D E F G
5 1 5 4 2
6 3 6 4 4
2 3 3 3 7
How to populate values of each parameter from df1 to df2 under same parameter which are present in first row as fields?
Create a row number column (rownames_to_column), gather into 'long' format, separate the 'val' column into two (by splitting at =- automatically picked up) and then spread into 'wide' format. By default, the elements that are missing are filled by NA. There is also a fill argument to change it to the desired fill value
library(tidyverse)
res <- df1 %>%
rownames_to_column('rn') %>%
gather(key, val, -rn) %>%
separate(val, into = c('val1', 'val2')) %>%
select(-key) %>%
spread(val1, val2) %>%
select(-rn)
res
# A B C D E F G
#1 5 <NA> 1 <NA> 5 4 2
#2 6 3 <NA> 6 4 4 <NA>
#3 <NA> 2 3 3 3 7 <NA>
If there is a second dataset containing some values and want to replace the non-NA elements in 'df2'
df2[!is.na(df2)] <- res[!is.na(df2)][names(df2)]
Or another option is dcast from data.table
library(data.table)
dcast(setDT(df1)[, tstrsplit(unlist(.SD), "="), .(grp = 1:nrow(df1))
], grp ~ V1, value.var = 'V2')[, grp := NULL][]
# A B C D E F G
#1: 5 NA 1 NA 5 4 2
#2: 6 3 NA 6 4 4 NA
#3: NA 2 3 3 3 7 NA
data
df1 <- structure(list(Col1 = c("A=5", "A=6", "B=2"), Col2 = c("C=1",
"B=3", "C=3"), Col3 = c("E=5", "D=6", "D=3"), Col4 = c("F=4",
"E=4", "E=3"), Col5 = c("G=2", "F=4", "F=7")), .Names = c("Col1",
"Col2", "Col3", "Col4", "Col5"), class = "data.frame", row.names = c(NA,
-3L))
来源：https://stackoverflow.com/questions/49377966/how-to-populate-parameters-values-present-in-rows-of-one-dataframedf1-to-dataf