How to extract first value from a list in R? (2024)

Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies

Selected Reading
UPSC IAS Exams Notes
Developer's Best Practices
Questions and Answers
Effective Resume Writing
HR Interview Questions
Computer Glossary
Who is Who

R ProgrammingServer Side ProgrammingProgramming

'; var adpushup = adpushup || {}; adpushup.que = adpushup.que || []; adpushup.que.push(function() { adpushup.triggerAd(ad_id); });

To extract first value from a list, we first need to access the element using double square brackets then the sub-element of each element will be accessed using single square brackets. For example, if we have a list called LIST containing five elements each having 10 elements then the first sub-element of the LIST will be selected by using LIST[[1]][1].

Example

Live Demo

List1<-list(x1=rnorm(50),x2=rnorm(50))List1

Output

$x1[1] 0.11130222 0.16419755 -0.52346744 2.06291702 1.75401221 1.76745535[7] 2.07647670 0.20604988 0.88090037 0.45002361 -0.41997558 0.13069306[13] 1.03792793 0.60365638 -0.86619055 -0.94122172 0.64561932 0.50256648[19] -0.61076372 0.90286990 -0.03448342 1.52897744 -0.12000996 0.07482846[25] -1.12145357 0.76479988 0.59701522 1.46033578 -0.57620173 -1.17224749[31] -0.73289297 -1.03691038 -1.28427938 -0.33767539 -1.01044720 0.22021704[37] 0.67931259 1.79052238 -0.80291917 -0.21613130 0.58112656 0.74238488[43] -0.37718519 1.31974664 2.33329258 0.33576900 -1.05233449 0.90282079[49] -0.23821323 -2.18185932$x2[1] 0.34801958 -0.24730876 -0.64642026 -0.20068985 0.94328680 -0.35876719[7] -0.65250327 -0.26434726 0.80161224 -1.98861577 -0.55784172 2.72095292[13] -0.34377048 -1.41075225 -0.58016709 0.30349424 -0.10171845 -1.63588095[19] 0.69116860 1.45962094 1.68120904 0.35287888 2.16297295 1.96956313[25] 0.20567607 0.39924676 0.18837752 -2.34209766 -0.49420627 -0.19967231[31] -0.06452823 -0.31314817 0.34765525 -0.31236504 -2.01858040 0.09302232[37] -0.07158963 0.91019112 -0.74267435 -0.40049302 0.18465365 0.65059368[43] 0.61031556 -0.23870247 -1.63562822 0.37430717 0.98758801 -0.09859013[49] 0.29618676 0.66022211

List1[[1]][1]

[1] 0.1113022

List1[[2]][1]

[1] 0.3480196

Example

Live Demo

List2<-list(y1=rpois(100,5),y2=rpois(100,5),y3=rpois(100,5),y4=rpois(100,5))List2

Output

$y1[1] 0 6 10 5 7 1 8 8 4 4 1 5 7 5 5 10 2 4 4 2 3 5 3 2 2[26] 5 4 12 4 4 5 4 4 6 6 5 7 10 1 3 9 4 6 3 7 6 4 3 6 5[51] 8 5 8 5 7 3 4 5 7 6 6 3 5 5 5 1 0 4 7 3 4 7 6 6 3[76] 3 3 4 3 5 6 4 6 3 4 4 6 7 8 4 3 10 11 6 8 8 6 6 7 4$y2[1] 7 7 11 4 4 1 4 7 2 6 2 2 6 2 2 6 3 3 6 2 5 6 6 5 6[26] 6 1 9 1 1 8 3 5 3 5 6 6 4 4 6 3 9 3 4 5 4 8 6 2 6[51] 6 2 8 8 8 5 4 1 3 7 8 6 6 10 6 8 5 2 4 7 4 8 4 3 8[76] 3 3 7 7 7 2 9 3 5 8 3 5 5 7 2 9 8 7 5 2 3 5 7 7 8$y3[1] 5 5 3 5 2 6 7 3 3 5 3 6 5 7 3 7 4 5 5 4 5 9 4 1 2[26] 4 5 5 5 5 4 3 2 6 8 4 13 6 4 6 7 5 5 6 2 3 6 4 4 6[51] 3 3 6 11 5 7 8 3 3 5 7 3 1 5 4 9 6 7 5 3 6 6 5 6 6[76] 6 6 2 12 2 1 7 3 6 4 5 4 3 4 3 5 6 4 3 8 6 7 7 7 5$y4[1] 6 7 4 6 6 1 7 6 2 6 10 7 5 9 9 3 6 6 10 4 7 4 2 4 10[26] 6 9 3 3 2 6 5 4 4 3 6 5 3 6 3 7 7 1 4 3 5 10 6 7 4[51] 5 3 6 8 3 5 4 5 5 5 6 3 4 10 5 3 7 5 5 7 4 4 3 5 6[76] 4 4 6 9 3 10 12 7 4 9 7 14 10 1 4 4 3 3 6 1 5 2 8 4 7

List2[[1]][1]

[1] 0

List2[[2]][1]

[1] 7

List2[[3]][1]

[1] 5

List2[[4]][1]

List2[[4]][1]

Example

Live Demo

List3<-list(z1=rexp(50),z2=rexp(50),z3=rexp(50),z4=rexp(50))List3

Output

$z1[1] 1.718907646 0.790585280 0.204750764 1.203047129 0.189730356 0.265698841[7] 0.471851353 1.178283257 0.278361849 1.725710894 0.004180386 1.500419515[13] 0.253964796 1.118053750 0.350007993 0.068681637 0.069928887 0.271137326[19] 0.316337873 1.513536640 0.608107488 0.100705733 0.091038117 1.680959338[25] 3.098310359 0.024069859 0.079393005 0.676481508 1.677929247 0.528531744[31] 0.952730628 0.605817827 0.552035683 0.179703399 0.029881320 1.763623732[37] 0.251440660 0.489608381 0.343958400 0.680817402 2.488113521 0.182692466[43] 1.838525970 0.026139385 1.336605331 0.187837140 1.001021679 1.068164745[49] 0.586717864 0.188288941$z2[1] 0.96681400 0.93182169 1.06428806 0.14140707 0.39303890 1.00227481[7] 0.02706789 2.80852463 1.71280020 1.03406754 1.00638814 0.70394098[13] 2.02029292 1.21125497 0.82803622 1.84601814 1.67267708 1.62547079[19] 1.43411676 1.07888560 0.26773645 1.22885541 1.12461358 0.97696734[25] 0.04547523 0.19367367 0.29813403 1.17887043 0.22968845 0.69612129[31] 0.60235370 3.02393213 2.27831540 2.85495798 0.57111993 3.15022562[37] 1.40904829 3.62419435 4.06618871 1.93677916 0.50544569 1.53942186[43] 4.00923268 0.06415687 0.16847399 0.95837914 2.17440413 0.69603180[49] 0.32872915 0.87998219$z3[1] 0.03984708 0.37911072 0.39527617 1.11247389 0.45724934 1.47759184[7] 0.90512793 0.35675484 0.88244845 0.12769840 0.00452113 0.53191616[13] 0.33870747 1.47954421 1.21998604 0.76498694 1.25436621 3.86274192[19] 0.86903165 1.02575073 3.26314757 0.96884011 2.99768499 0.73019254[25] 0.81639460 0.69500919 1.32349089 2.55732287 0.86032776 0.21881670[31] 0.23084453 0.01074831 0.48422758 0.48439722 1.38000094 0.30889465[37] 1.19599421 0.60671956 1.16873709 0.99445705 0.74635728 0.40339360[43] 1.32840395 2.92880480 1.04132163 1.68629929 0.25703192 0.68822688[49] 0.92138168 0.43555544$z4[1] 0.019785280 0.332113114 0.603268548 1.475968243 0.404461872 0.084103244[7] 0.802729027 1.684216058 2.004364217 1.100479145 0.268109553 2.453706887[13] 0.716849180 0.045104141 0.386609886 0.149478953 1.209757102 0.941370074[19] 1.726784369 0.681956061 0.427254268 0.830936060 0.692974098 0.716479172[25] 1.624493349 0.216954219 0.384070517 0.516003236 2.268504498 0.750347184[31] 2.898988536 0.022540033 0.069682582 0.324829354 0.005932369 1.836073771[37] 0.608267033 1.554355547 0.664473031 0.228425454 1.815967761 0.046082996[43] 0.865417744 0.063441784 0.015283203 0.517283282 4.257718179 0.228973207[49] 0.870923003 1.105269648

List3[[1]][1]

[1] 1.718908

List3[[2]][1]

[1] 0.966814

List3[[3]][1]

Kickstart Your Career

Get certified by completing the course

Get Started

Advertisem*nts

';adpushup.triggerAd(ad_id); });

FAQs

How to extract first value from a list in R? ›

To extract only first element from a list, we can use sapply function and access the first element with double square brackets. For example, if we have a list called LIST that contains 5 elements each containing 20 elements then the first sub-element can be extracted by using the command sapply(LIST,"[[",1).

How do I extract a specific value from a list in R? ›

The [[ operator can be used to extract single elements from a list. Here we extract the first element of the list. The [[ operator can also use named indices so that you don't have to remember the exact ordering of every element of the list. You can also use the $ operator to extract elements by name.

Keep Reading ›

How do you find the first value in a list? ›

To get the first item you must use the index 0 . This "zero-indexing" is very common and is used by most programming languages.

Discover More Details ›

How to select the first value of a variable in R? ›

To extract first value from a list, we first need to access the element using double square brackets then the sub-element of each element will be accessed using single square brackets.

Discover More ›

How do I get the first N element of a list in R? ›

How to extract the first n values of all elements of a list in R?

First of all, create a list.
Then, use head function with sapply function to extract the first n values of all elements in the list.

Nov 9, 2021

Read The Full Story ›

How to extract the first element of a list in R? ›

How do I extract a value from a list? ›

Step-by-step approach:

Initialize the original list and K value.
Create an empty list to store the extracted elements.
Loop through the list using the enumerate() function to access both the index and value of each element in the list.

More items...

May 10, 2023

Tell Me More ›

How do you find the first occurrence of a value in a list? ›

index() function is a built-in method that returns the index of the first occurrence of an item in a list. It's a simple and straightforward way to locate an item in a list. In the above snippet, my_list. index('banana') returns '1', which is the index of 'banana' in the list my_list .

Get More Info Here ›

How do you find the first value of an array list? ›

Get the first element of ArrayList with use of get(index) method by passing index = 0.

Get More Info ›

How to get the first element of a nested list? ›

To access values inside a nested list in Python, you can use square brackets to chain multiple index accesses together. For example, to access the first element of the second sublist in a nested list called my_list, you can use my_list[1][0].

View Details ›

How do I select a value from a list in R? ›

We need to use the [[index]] to select an element in a list. The value inside the double square bracket represents the position of the item in a list we want to extract. For instance, we pass 2 inside the parenthesis, R returns the second element listed.

Show Me More ›

How to select first element in data frame in R? ›

Similar to vectors and matrices, you select elements from a data frame with the help of square brackets [ ] . By using a comma, you can indicate what to select from the rows and the columns respectively. For example: my_df[1,2] selects the value at the first row and second column in my_df .

How do I select a specific value in R? ›

To limit your dataset to a subset of observations in base R, use brackets [ ] or subset() . With brackets you can subset based on row numbers, row names, or a logical expression. With subset() , you must use a logical expression.

Tell Me More ›

How do you access the first element of a list? ›

Lists work similarly to strings -- use the len() function and square brackets [ ] to access data, with the first element at index 0.

View Details ›

How do I find one element from a list? ›

Find if an an element exists in list using filter() Function

Define the list my_list and Set element_to_check.
Use the filter() function to create an iterator (filtered_elements) that contains elements equal to the element_to_check.
Convert the iterator filtered_elements to a list.

More items...

Mar 26, 2024

Discover More ›

How do you pop the first element in a list? ›

The second item has an index of 1 , and so on. So, to remove the first item in a list, you specify an index of 0 as the parameter to the pop() method. And remember, pop() returns the item that has been removed.

Get More Info Here ›

How do I get a specific value from a list? ›

The index() function returns the index of the element in the list, and you can use this index to get the value of the element. Note that if the element does not exist in the list, the index() function will raise a ValueError .

How to extract first value from a list in R? (2024)

Example

Output

Example

Output

Example

Output

Kickstart Your Career

FAQs

How to extract first value from a list in R? ›

How do I select a value from a list in R? ›

References