R 统一使用字符串中的一位数和两位数
我有一个非常大的data.table,其中(大量)项由字符串定义,包括文本和数字R 统一使用字符串中的一位数和两位数,r,string,data.table,data-management,R,String,Data.table,Data Management,我有一个非常大的data.table,其中(大量)项由字符串定义,包括文本和数字 library(data.table) dd <- data.table(x = c("A4","A4","A4","A14","A14","A14","B4","B4","B4"),y = c("A4","A14","B4","A4","A14","B4","A4","A14","B4"), z = c(1,2,3,4,5,6,7,8,9)) x y z A4 A4 1 A4 A14
library(data.table)
dd <- data.table(x = c("A4","A4","A4","A14","A14","A14","B4","B4","B4"),y = c("A4","A14","B4","A4","A14","B4","A4","A14","B4"), z = c(1,2,3,4,5,6,7,8,9))
x y z
A4 A4 1
A4 A14 2
A4 B4 3
A14 A4 4
A14 A14 5
A14 B4 6
B4 A4 7
B4 A14 8
B4 B4 9
但是,我需要以下矩阵计算的原始顺序。有没有什么有效的方法可以将string+一位数重命名为string+两位数(A4->A04)或其他我错过的方法 您可以使用sprintf()
预先为数字添加0
sprintf("%s%02.0d", "A", 1:20)
# [1] "A01" "A02" "A03" "A04" "A05" "A06" "A07" "A08" "A09" "A10" "A11" "A12" "A13" "A14" "A15" "A16" "A17" "A18" "A19" "A20"
您可以使用将
0
s添加到数据中
dd[nchar(x) == 2, x := paste0(substr(x, 1, 1), 0, substr(x, 2, 2))]
dd[nchar(y) == 2, y := paste0(substr(y, 1, 1), 0, substr(y, 2, 2))]
# x y z
# 1: A04 A04 1
# 2: A04 A14 2
# 3: A04 B04 3
# 4: A14 A04 4
# 5: A14 A14 5
# 6: A14 B04 6
# 7: B04 A04 7
# 8: B04 A14 8
# 9: B04 B04 9
或者,如果需要应用于更多列:
to.change <- c('x', 'y')
dd[, (to.change) := lapply(.SD, function(x) ifelse(nchar(x) > 2, x
, paste0(substr(x, 1, 1), 0, substr(x, 2, 2))))
, .SDcols = to.change]
to.change 2,x
,粘贴0(substr(x,1,1),0,substr(x,2,2)))
,.SDcols=to.change]
此解决方案中不需要额外的零
# Data frame
df <- data.frame(x = c("A4","A4","A4","A14","A14","A14","B4","B4","B4"),
y = c("A4","A14","B4","A4","A14","B4","A4","A14","B4"),
z = c(1,2,3,4,5,6,7,8,9),
stringsAsFactors = FALSE)
# Reorder columns and rows using `mixedsort`.
wide <- dcast(df, x ~ y,value.var = "z") %>%
select(x, mixedsort(unique(df$x))) %>%
slice(match(x, mixedsort(unique(df$x))))
另一个可能也是最简单的选择是使用
gtools
-包中的mixedorder
:
wide <- dcast(dd, x ~ y, value.var = "z")[gtools::mixedorder(x)]
如果还希望以相同的方式设置列顺序,可以另外使用setcolorder
:
setcolorder(wide, c(1, gtools::mixedorder(names(wide)[-1]) + 1))
然后给出:
<>您可能想考虑通过数据直接在数据中实现这一顺序,因此您不必在以后的数据冲突中修复它。 如果已经在某个地方对这些唯一值进行了排序,则不需要
mixedorder
而不需要mixedorder
,只需将它们转换为因子即可
否则您可以取回订单:
library(gtools)
dd[,1:2] <- lapply(dd[,1:2],function(x) factor(x, mixedsort(unique(x))))
我认为最好使用整数格式,如
“%s%02d”
。无论如何,投票吧。
wide <- dcast(dd, x ~ y, value.var = "z")[gtools::mixedorder(x)]
> wide
x A14 A4 B4
1: A4 2 1 3
2: A14 5 4 6
3: B4 8 7 9
setcolorder(wide, c(1, gtools::mixedorder(names(wide)[-1]) + 1))
> wide
x A4 A14 B4
1: A4 1 2 3
2: A14 4 5 6
3: B4 7 8 9
library(gtools)
dd[,1:2] <- lapply(dd[,1:2],function(x) factor(x, mixedsort(unique(x))))
dcast(dd, x ~ y, value.var = "z")
# x A4 A14 B4
# 1: A4 1 2 3
# 2: A14 4 5 6
# 3: B4 7 8 9