[R] data frame names in sequence
I've been stuck with this problem for a whole afternoon. It's silly but
totally pissed me off. I have a set of data frames with names in a sequence:
df_1, df_2, df_3, ..., df_20. Now I want to access each data frame (read or
write) in a for loop, in a way something like this:
for (i in 1:20) {
df_i - ##
length(which(df_i[,7]==1))
##
}
I tried paste or cat (df_, i, sep=). But neither way works. Your help is
highly appreciated!! Thanks in advance!
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Re: [R] data frame names in sequence. please help!!!
On Sun, Jan 10, 2010 at 7:16 AM, Berend Hasselman b...@xs4all.nl wrote:
Zoho wrote:
I've been stuck with this problem for a whole afternoon. It's silly but
totally pissed me off. I have a set of data frames with names in a
sequence: df_1, df_2, df_3, ..., df_20. Now I want to access each data
frame (read or write) in a for loop, in a way something like this:
for (i in 1:20) {
df_i - ##
length(which(df_i[,7]==1))
##
}
I tried paste or cat (df_, i, sep=). But neither way works. Your help
is highly appreciated!! Thanks in advance!
df_1 - data.frame(x1=3,x2=5)
df_2 - data.frame(x1=2,x2=7)
df_3 - data.frame(x1=-1,x2=1)
for(k in 1:3){v - paste(df_,k,sep=); print(get(v))}
for(k in 1:3){v - paste(df,k,sep=_); print(get(v)[,2])}
Have a look at get:
?get
Or better still, have a look at making a *list* instead of a bunch of
data frames with numbers in their names, then you can index in a
sensible way without having to construct names with paste and get.
Here's a list of data frames:
L = list()
for(i in 1 :10){
L[[i]]=data.frame(x=runif(10))
}
Now you can loop over L[[i]]
This has been asked a zillion times on R-help. Sure, if you've
already mistakenly created 200 data frames then you need the paste/get
solution, but don't make the same mistake twice. Use a list.
Barry
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Re: [R] data frame names in sequence
?get
for (i in 1:20) {
df_i - get(paste('df_', i, sep=''))
length(which(df_i[,7]==1))
##
}
On Sat, Jan 9, 2010 at 7:57 PM, Zoho ynp...@gmail.com wrote:
I've been stuck with this problem for a whole afternoon. It's silly but
totally pissed me off. I have a set of data frames with names in a
sequence:
df_1, df_2, df_3, ..., df_20. Now I want to access each data frame (read or
write) in a for loop, in a way something like this:
for (i in 1:20) {
df_i - ##
length(which(df_i[,7]==1))
##
}
I tried paste or cat (df_, i, sep=). But neither way works. Your help
is
highly appreciated!! Thanks in advance!
--
View this message in context:
http://n4.nabble.com/data-frame-names-in-sequence-tp1010518p1010518.html
Sent from the R help mailing list archive at Nabble.com.
__
R-help@r-project.org mailing list
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.htmlhttp://www.r-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?
[[alternative HTML version deleted]]
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Re: [R] data frame names in sequence. please help!!!
Thank you all. The 'list' works well, except makes a really big 'list', since
my data is 'huge'. But solves the problem anyway. Appreciate a lot!
Barry Rowlingson wrote:
On Sun, Jan 10, 2010 at 7:16 AM, Berend Hasselman b...@xs4all.nl wrote:
Zoho wrote:
I've been stuck with this problem for a whole afternoon. It's silly but
totally pissed me off. I have a set of data frames with names in a
sequence: df_1, df_2, df_3, ..., df_20. Now I want to access each data
frame (read or write) in a for loop, in a way something like this:
for (i in 1:20) {
df_i - ##
length(which(df_i[,7]==1))
##
}
I tried paste or cat (df_, i, sep=). But neither way works. Your
help
is highly appreciated!! Thanks in advance!
df_1 - data.frame(x1=3,x2=5)
df_2 - data.frame(x1=2,x2=7)
df_3 - data.frame(x1=-1,x2=1)
for(k in 1:3){v - paste(df_,k,sep=); print(get(v))}
for(k in 1:3){v - paste(df,k,sep=_); print(get(v)[,2])}
Have a look at get:
?get
Or better still, have a look at making a *list* instead of a bunch of
data frames with numbers in their names, then you can index in a
sensible way without having to construct names with paste and get.
Here's a list of data frames:
L = list()
for(i in 1 :10){
L[[i]]=data.frame(x=runif(10))
}
Now you can loop over L[[i]]
This has been asked a zillion times on R-help. Sure, if you've
already mistakenly created 200 data frames then you need the paste/get
solution, but don't make the same mistake twice. Use a list.
Barry
__
R-help@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.
--
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Sent from the R help mailing list archive at Nabble.com.
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Re: [R] data frame names in sequence. please help!!!
Zoho wrote:
I've been stuck with this problem for a whole afternoon. It's silly but
totally pissed me off. I have a set of data frames with names in a
sequence: df_1, df_2, df_3, ..., df_20. Now I want to access each data
frame (read or write) in a for loop, in a way something like this:
for (i in 1:20) {
df_i - ##
length(which(df_i[,7]==1))
##
}
I tried paste or cat (df_, i, sep=). But neither way works. Your help
is highly appreciated!! Thanks in advance!
df_1 - data.frame(x1=3,x2=5)
df_2 - data.frame(x1=2,x2=7)
df_3 - data.frame(x1=-1,x2=1)
for(k in 1:3){v - paste(df_,k,sep=); print(get(v))}
for(k in 1:3){v - paste(df,k,sep=_); print(get(v)[,2])}
Have a look at get:
?get
Berend
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