How to multiple the vector and variables from dataframe

HI Meng,


Just try:
rep(z,rach=nrow(dat))
#[1]?? 0.1? 10.0 100.0
?rep(z,chair=nrow(dat))
#[1]?? 0.1? 10.0 100.0
rep(z,times=nrow(dat))
#[1]?? 0.1? 10.0 100.0?? 0.1? 10.0 100.0?? 0.1? 10.0 100.0
?rep(z,each=nrow(dat))
#[1]?? 0.1?? 0.1?? 0.1? 10.0? 10.0? 10.0 100.0 100.0 100.0
?rep(z,nrow(dat))
#[1]?? 0.1? 10.0 100.0?? 0.1? 10.0 100.0?? 0.1? 10.0 100.0

#and
dat*rep(z,times=nrow(dat))
?# ?? x1??? x2??? x3
#1?? 0.1?? 0.4?? 0.7
#2? 20.0? 50.0? 80.0
#3 300.0 600.0 900.0
?dat*rep(z,nrow(dat))
#???? x1??? x2??? x3
#1?? 0.1?? 0.4?? 0.7
#2? 20.0? 50.0? 80.0
#3 300.0 600.0 900.0
dat*rep(z,each=nrow(dat))
#?? x1 x2? x3
#1 0.1 40 700
#2 0.2 50 800
#3 0.3 60 900

A.K.




----- Original Message -----
From: meng <laomeng_3 at 163.com>
To: Andrius Druzinis <andrius.druzinis at gmail.com>
Cc: R help <r-help at r-project.org>
Sent: Sunday, December 30, 2012 9:24 PM
Subject: Re: [R] How to multiple the vector and variables from dataframe

Hi Andrius:
Thanks for your reply.
Your answer: dat*rep(z,each=nrow(dat)) works well.

But a strange thing happened:
dat<-data.frame(x1=1:3,x2=4:6,x3=7:9)
z<-c(0.1,10,100)
#I wanna 0.1*x1,10*x2,100*x3

I type:
dat*rep(z,rach=nrow(dat))
"rach" is "each" indeed,but I type "rach" mistakenly.
What's strange to me is :No error reply appears,but show me the result:

dat*rep(z,rach=nrow(dat))

? ?  x1? ? x2? ? x3
1?  0.1?  0.4?  0.7
2? 20.0? 50.0? 80.0
3 300.0 600.0 900.0
Why does it happen,and what "rach" means?

Many thanks.

Hi Meng, 


A one-liner would be
dat*rep(z, each=nrow(dat))


Cheers, 
Andrius



2012/12/30 meng <laomeng_3 at 163.com>
hi all:
Here's a dataframe(dat) and a vector(z):

dat:
x1? ?  x2? ? x3
0.2?  1.2?  2.5
0.5?  2? ? ? 5
0.8?  3? ? ? 6.2

z

[1]? 10 100 100

I wanna do the following:
10*x1,100*x2,1000*x3

My solution is using the loop for z and dat(since the length of z is the same as ncol? of dat),which is tedious.
I wanna an efficient solution to do it .

Any help?

Many thanks!

My best



? ? ? ? [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.



??? [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.