Dear Rui,
THanks for your reply...The point is the loop is a scraping
code, and in your examples you have assumed that the body acts on i, the loop
variable. Can you adapt your code to JUST PRINT the loop variable i ?
By the by, I think I have stumbled upon the answer: The lapply() caches the
result, and prints the output of the function in question immediately after
printing the final i. The i's get printed serially, as the function
progresses....
> lapply(1:4,function(x){print(x);Sys.sleep(x^2);x^2})
[1] 1
[1] 2
[1] 3
[1] 4
[[1]]
[1] 1
[[2]]
[1] 4
[[3]]
[1] 9
[[4]]
[1] 16
Here x^2 's print only after 4 is printed on the console....
tHanks anyways for your reply....
THanking you,
Yours sincerely,
AKSHAY M KULKARNI
________________________________
From: Rui Barradas <ruipbarra...@sapo.pt>
Sent: Tuesday, November 8, 2022 12:24 AM
To: akshay kulkarni <akshay...@hotmail.com>; R help Mailing list
<r-help@r-project.org>
Subject: Re: [R] print and lapply....
�s 18:33 de 07/11/2022, akshay kulkarni escreveu:
> Dear Rui,
> Actually, I am replacing a big for loop by the lapply()
> function, and report the progress:
>
> lapply(TP, function(i) { BODY; print(i)})
>
> Can you please adjust your solution in this light?
>
> THanking you,
> Yours sincerely,
> AKSHAY M KULKARNI
> ________________________________
> From: Rui Barradas <ruipbarra...@sapo.pt>
> Sent: Monday, November 7, 2022 11:59 PM
> To: akshay kulkarni <akshay...@hotmail.com>; R help Mailing list
> <r-help@r-project.org>
> Subject: Re: [R] print and lapply....
>
> �s 17:17 de 07/11/2022, akshay kulkarni escreveu:
>> Dear members,
>> I have the following code and output:
>>
>>> TP <- 1:4
>>> lapply(TP,function(x){print(x);x^2})
>> [1] 1
>> [1] 2
>> [1] 3
>> [1] 4
>> [[1]]
>> [1] 1
>>
>> [[2]]
>> [1] 4
>>
>> [[3]]
>> [1] 9
>>
>> [[4]]
>> [1] 16
>>
>> How do I make the print function output x along with x^2, i.e not at the
>> beginning but before each of x^2?
>>
>> Many thanks in advance....
>>
>> THanking you,
>> Yours sincerely
>> AKSHAY M KULKARNI
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
> Hello,
>
> Here are two options, with ?cat and with ?message.
>
>
> TP <- 1:4
> lapply(TP, function(x){
> cat("x =", x, "x^2 =", x^2, "\n")
> })
>
> lapply(TP, function(x){
> msg <- paste("x =", x, "x^2 =", x^2)
> message(msg)
> })
>
>
> Hope this helps,
>
> Rui Barradas
>
>
>
Hello,
What do you want the lapply loop to return? If you have a BODY doing
computations, do you want the lapply to return those values and report
the progress?
I have chosen cat or message over print because
- cat returns invisible(NULL),
- message returns invisible()
- print returns a value, what it prints.
Can you adapt the code below to your use case?
TP <- 1:4
lapply(TP, function(x, verbose = TRUE){
# BODY
y <- rnorm(100, mean = x)
# show progress
if(verbose)
cat("x =", x, "x^2 =", x^2, "\n")
#return value
c(x = x, mean = mean(y))
})
lapply(TP, function(x, verbose = TRUE){
# BODY
y <- rnorm(100, mean = x)
# show progress
if(verbose) {
msg <- paste("x =", x, "x^2 =", x^2)
message(msg)
}
#return value
c(x = x, mean = mean(y))
})
Hope this helps,
Rui Barradas
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
