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Extract every 2 element for a list which are not equal in length

5 messages · Jim Lemon, Jorge I Velez, Mohammad Tanvir Ahamed

#
Hi,

a <- c(1:5)b <- c(1:3)
c <- 1
d <- 5
e <- list(a,b,c,d)

# To extract every 1st element 
lapply(e,"[[",1)

## Out-put 
[[1]] 
[1] 1 

[[2]] 
[1] 1 

[[3]] 
[1] 1 

[[4]] 
[1] 5
 
#To extract every 2nd element (Need help in this case)
lapply(e,"[[",2)

## Expected outcome 
[[1]] 
[1] 2 

[[2]] 
[1] 2 

[[3]] 
[1] NA 

[[4]] 
[1] NA 



Any help will be appreciated . Thanks 


Tanvir Ahamed 
G?teborg, Sweden  |  mashranga at yahoo.com
#
Hi Tanvir,
I think what you want is:

lapply(e,"[",1)
lapply(e,"[",2)

Jim


On Tue, Mar 8, 2016 at 11:47 AM, Mohammad Tanvir Ahamed via R-help
<r-help at r-project.org> wrote:
#
Dear Mohammad,
What's wrong with the result?
Best,
Jorge.-

On Monday, March 7, 2016, Mohammad Tanvir Ahamed via R-help <
r-help at r-project.org> wrote:

            

  
    
#
Hi Jim,
 
Thanks . Some how i have messed up mu lapply function.
Worked upon restart. 
 
Tanvir Ahamed 
G?teborg, Sweden   |  mashranga at yahoo.com 


----- Original Message -----
From: Jim Lemon <drjimlemon at gmail.com>
To: Mohammad Tanvir Ahamed <mashranga at yahoo.com>
Cc: R-help Mailing List <r-help at r-project.org>
Sent: Tuesday, 8 March 2016, 3:00
Subject: Re: [R] Extract every 2 element for a list which are not equal in length

Hi Tanvir,
I think what you want is:

lapply(e,"[",1)
lapply(e,"[",2)

Jim



On Tue, Mar 8, 2016 at 11:47 AM, Mohammad Tanvir Ahamed via R-help
<r-help at r-project.org> wrote:
#
Hi Jorge,?
Thanks . Some how i have messed up mu lapply function.Worked upon restart.??Tanvir Ahamed 
   G?teborg, Sweden     |  mashranga at yahoo.com 

      From: Jorge I Velez <jorgeivanvelez at gmail.com>
 To: Mohammad Tanvir Ahamed <mashranga at yahoo.com> 
Cc: R-help Mailing List <r-help at r-project.org>
 Sent: Tuesday, 8 March 2016, 3:04
 Subject: Re: [R] Extract every 2 element for a list which are not equal in length
   
Dear Mohammad,What's wrong with?the result?Best,Jorge.-
On Monday, March 7, 2016, Mohammad Tanvir Ahamed via R-help <r-help at r-project.org> wrote:
Hi,

a <- c(1:5)b <- c(1:3)
c <- 1
d <- 5
e <- list(a,b,c,d)

# To extract every 1st element
lapply(e,"[[",1)

## Out-put
[[1]]
[1] 1

[[2]]
[1] 1

[[3]]
[1] 1

[[4]]
[1] 5

#To extract every 2nd element (Need help in this case)
lapply(e,"[[",2)

## Expected outcome
[[1]]
[1] 2

[[2]]
[1] 2

[[3]]
[1] NA

[[4]]
[1] NA



Any help will be appreciated . Thanks


Tanvir Ahamed
G?teborg, Sweden? |? mashranga at yahoo.com

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