I'm trying to repeat the elements of vector a, b number of times. That is, a="abc" should be "aabbcc" if y = 2.
我试图重复矢量a，b的元素次数。也就是说，如果y = 2，则a =“abc”应为“aabbcc”。
Why doesn't either of the following code examples work?
为什么以下任何一个代码示例都不起作用？
sapply(a, function (x) rep(x,b))
and from the plyr package,
从plyr包装，
aaply(a, function (x) rep(x,b))
I know I'm missing something very obvious ...
我知道我错过了一些非常明显的东西......
2 个解决方案
#1
10
Assuming you a is a vector, sapply will create a matrix that just needs to be collapsed back into a vector:
假设你是一个向量，sapply会创建一个只需要折叠回向量的矩阵：
a<-c("a","b","c")
b<-3 # Or some other number
a<-sapply(a, function (x) rep(x,b))
a<-as.vector(a)
Should create the following output:
应该创建以下输出：
"a" "a" "a" "b" "b" "b" "c" "c" "c"
#2
16
a is not a vector, you have to split the string into single characters, e.g.
a不是矢量，你必须将字符串拆分成单个字符，例如
R> paste(rep(strsplit("abc","")[[1]], each=2), collapse="")
[1] "aabbcc"
#1
10
Assuming you a is a vector, sapply will create a matrix that just needs to be collapsed back into a vector:
假设你是一个向量，sapply会创建一个只需要折叠回向量的矩阵：
a<-c("a","b","c")
b<-3 # Or some other number
a<-sapply(a, function (x) rep(x,b))
a<-as.vector(a)
Should create the following output:
应该创建以下输出：
"a" "a" "a" "b" "b" "b" "c" "c" "c"
#2
16
a is not a vector, you have to split the string into single characters, e.g.
a不是矢量，你必须将字符串拆分成单个字符，例如
R> paste(rep(strsplit("abc","")[[1]], each=2), collapse="")
[1] "aabbcc"