How to get values from a list?

Question

I have a list with uniform size as below. I want to extract the values for the keys. How do I do it?

I have isolated the keys by using names(allsum) where allsum looks like this

`$1999
[1] 7332967

$2002
[1] 5635780

$2005
[1] 5454703

$2008
[1] 3464206`

I want [7332967, 5635780, 5454703, 3464206] as the output. I tried sapply but have a weak intuition. Please help.

for(a in allsum) {
  print(a[[1]])
}

I tried this, it works, but I want to know if we can do it with some function or without any explicit looping.

I tried using unlist Following is what happens

c1 <- unlist(allsum) 
 #1999    2002    2005    2008 
#7332967 5635780 5454703 3464206

I just need the big numbers. How do I extract?

If you use `lapply` and getting this as an output, consider using [`sapply`](https://stackoverflow.com/a/7141669/1030110). — m0nhawk, May 31 '17 at 06:33
What you get with just `v1 <- unlist(allsum)` is a named vector, which is still a numeric vector. For example you can try `v1 + 1000` or do `as.data.frame(v1)`, or `names(v1)` and `unname(v1)` — Sotos, May 31 '17 at 07:20
Perfect @Sotos I thing unname() is the right thing to do!! Thanks!! — Niranjan Agnihotri, May 31 '17 at 07:27

score 12 · Answer 1 · answered May 31 '17 at 07:30

12

@Sotos thanks a lot.

I think I was just looking for this!!

unname(unlist(allsum))

answered May 31 '17 at 07:30

Niranjan Agnihotri

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Also works as `unlist(unname(cols_dict))`. – Kaleb Coberly Dec 21 '21 at 23:50

KenHBS · Accepted Answer · 2017-05-31T07:20:11.953

7

What about

allsum <- list(`1999` = 7332967, `2002` = 5635780, 
               `2005` = 5454703, `2008` = 3464206)   

paste(unlist(allsum))
# [1] "7332967" "5635780" "5454703" "3464206"

Edit:

As pointed out in the comments, paste will convert the numerical values in to strings.

You can either solve the problem create by paste(unlist(allsum)) with:

as.numeric(paste(unlist(allsum))
# [1] 7332967 5635780 5454703 3464206

Or avoid that issue altogether by using Sotos' suggestion in the comments:

unname(unlist(allsum))
# [1] 7332967 5635780 5454703 3464206

edited May 31 '17 at 07:20

answered May 31 '17 at 06:48

KenHBS

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Works fine!! Thanks a lot Could you please explain how it works as only using `unlist` we just get both the keys and values – Niranjan Agnihotri May 31 '17 at 06:55
2

I would NOT recommend that. It converts the values to character. Why not simply `unname`? – Sotos May 31 '17 at 07:13

Uwe · Answer 3 · 2017-05-31T22:59:37.527

4

Please, try

as.integer(allsum)
#[1] 7332967 5635780 5454703 3464206

edited May 31 '17 at 22:59

answered May 31 '17 at 07:30

Uwe

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score 0 · Answer 4 · answered May 31 '17 at 06:31

0

To get, the values of list as a vector, you should do:

unlist(allsum)

answered May 31 '17 at 06:31

Pop

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I used the unlist and got the above output – Niranjan Agnihotri May 31 '17 at 06:40

How to get values from a list?

4 Answers4

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