问题
I have two lists named h and g.
They each contain 244 dataframes and they look like the following:
h[[1]]
year avg hr sal
1 2010 0.300 31 2000
2 2011 0.290 30 4000
3 2012 0.275 14 600
4 2013 0.280 24 800
5 2014 0.295 18 1000
6 2015 0.330 26 7000
7 2016 0.315 40 9000
g[[1]]
year pos fld
1 2010 A 0.990
2 2011 B 0.995
3 2013 C 0.970
4 2014 B 0.980
5 2015 D 0.990
I want to cbind these two dataframes.
But as you see, they have different number of rows.
I want to combine these dataframes so that the rows with the same year will be combined in one row. And I want the empty spaces to be filled with NA.
The result I expect looks like this:
year avg hr sal pos fld
1 2010 0.300 31 2000 A 0.990
2 2011 0.290 30 4000 B 0.995
3 2012 0.275 14 600 NA NA
4 2013 0.280 24 800 C 0.970
5 2014 0.295 18 1000 B 0.980
6 2015 0.330 26 7000 D 0.990
7 2016 0.315 40 9000 NA NA
Also, I want to repeat this for all the 244 dataframes in each list, h and g.
I'd like to make a new list named final which contains the 244 combined dataframes.
How can I do this...? All answers will be greatly appreciated :)
回答1:
I think you should instead use merge:
merge(df1, df2, by="year", all = T)
For your data:
df1 = data.frame(matrix(0, 7, 4))
names(df1) = c("year", "avg", "hr", "sal")
df1$year = 2010:2016
df1$avg = c(.3, .29, .275, .280, .295, .33, .315)
df1$hr = c(31, 30, 14, 24, 18, 26, 40)
df1$sal = c(2000, 4000, 600, 800, 1000, 7000, 9000)
df2 = data.frame(matrix(0, 5, 3))
names(df2) = c("year", "pos", "fld")
df2$year = c(2010, 2011, 2013, 2014, 2015)
df2$pos = c('A', 'B', 'C', 'B', 'D')
df2$fld = c(.99,.995,.97,.98,.99)
cbind is meant to column-bind two dataframes that are in all sense compatible. But what you aim to do is actual merge, where you want the elements from the two data frames not be discarded, and for missing values you get NA instead.
回答2:
We can use Map with cbind.fill (from rowr) to cbind the corresponding 'data.frame' from 'h' and 'g'.
library(rowr)
Map(cbind.fill, h, g, MoreArgs = list(fill=NA))
Update
Based on the expected output showed, it seems like the OP wanted a merge instead of cbind
f1 <- function(...) merge(..., all = TRUE, by = 'year')
Map(f1, h, g)
#[[1]]
# year avg hr sal pos fld
#1 2010 0.300 31 2000 A 0.990
#2 2011 0.290 30 4000 B 0.995
#3 2012 0.275 14 600 <NA> NA
#4 2013 0.280 24 800 C 0.970
#5 2014 0.295 18 1000 B 0.980
#6 2015 0.330 26 7000 D 0.990
#7 2016 0.315 40 9000 <NA> NA
Or as @Colonel Beauvel mentioned, this can be made compact
Map(merge, h, g, by='year', all=TRUE)
data
h <- list(structure(list(year = 2010:2016, avg = c(0.3, 0.29, 0.275,
0.28, 0.295, 0.33, 0.315), hr = c(31L, 30L, 14L, 24L, 18L, 26L,
40L), sal = c(2000L, 4000L, 600L, 800L, 1000L, 7000L, 9000L)), .Names = c("year",
"avg", "hr", "sal"), class = "data.frame", row.names = c("1",
"2", "3", "4", "5", "6", "7")))
g <- list(structure(list(year = c(2010L, 2011L, 2013L, 2014L, 2015L
), pos = c("A", "B", "C", "B", "D"), fld = c(0.99, 0.995, 0.97,
0.98, 0.99)), .Names = c("year", "pos", "fld"), class = "data.frame",
row.names = c("1",
"2", "3", "4", "5")))
回答3:
Here is how you could do this with tidyverse tools:
library(tidyverse)
h <- list()
g <- list()
h[[1]] <- tribble(
~year, ~avg, ~hr, ~sal,
2010, 0.300, 31, 2000,
2011, 0.290, 30, 4000,
2012, 0.275, 14, 600,
2013, 0.280, 24, 800,
2014, 0.295, 18, 1000,
2015, 0.330, 26, 7000,
2016, 0.315, 40, 9000
)
g[[1]] <- tribble(
~year, ~pos, ~fld,
2010, "A", 0.990,
2011, "B", 0.995,
2013, "C", 0.970,
2014, "B", 0.980,
2015, "D", 0.990
)
map2(h, g, left_join)
Which produces:
[[1]]
# A tibble: 7 x 6
year avg hr sal pos fld
<dbl> <dbl> <dbl> <dbl> <chr> <dbl>
1 2010 0.3 31 2000 A 0.99
2 2011 0.290 30 4000 B 0.995
3 2012 0.275 14 600 NA NA
4 2013 0.28 24 800 C 0.97
5 2014 0.295 18 1000 B 0.98
6 2015 0.33 26 7000 D 0.99
7 2016 0.315 40 9000 NA NA
来源：https://stackoverflow.com/questions/40399229/cbind-2-dataframes-with-different-number-of-rows