#data.frame

Matching data with different sizes from different data.frames

두 개의 데이터 프레임이 있는데, date라는 공통의 컬럼을 가지고 있다. 이때 각각의 date컬럼에서 일치하는 경우 나머지 컬럼을 모아서 하나로 만드는 소스이다. apply같은 걸로 루프를 사용안할 수 도 있을 것 같은데, 바빠서 대강…. a <- data.frame(matrix(c(1,2, 3,4, 5,6, 7,8), nrow=4, byrow=T, dimnames = list(NULL, c("date","price"))) ) b <- data.frame(matrix(c(1,2, 9,4, 3,6, 8,6, 0,6, 7,9), nrow=6, byrow=T, dimnames = list(NULL, c("date","price"))) ) cc <- data.frame() for(i in…

How-to: dropping factor levels in a subsetted data frame in R #fix #it #programming

dropping factor levels in a subsetted data frame in R

I have a data frame containing a factor. When I create a subset of this data frame using subset() or another indexing function, a new data frame is created. However, the factor variable retains all of its original levels even when they do not exist in the new data frame.

This creates headaches when doing faceted plotting or using functions…

Fixed Quickly reading very large tables as dataframes in R #dev #it #asnwer

Quickly reading very large tables as dataframes in R

I have very large tables (30 million rows) that I would like to load as a dataframes in R. read.table()has a lot of convenient features, but it seems like there is a lot of logic in the implementation that would slow things down. In my case, I am assuming I know the types of the columns ahead of time, the table does not contain any column…

Fixed remove rows with NAs in data.frame #dev #it #asnwer

remove rows with NAs in data.frame

I’d like to remove the lines in this dataframe that contain NAs across all columns. Below is my example data.frame.

gene hsap mmul mmus rnor cfam 1 ENSG00000208234 0 NA NA NA NA 2 ENSG00000199674 0 2 2 2 2 3 ENSG00000221622 0 NA NA NA NA 4 ENSG00000207604 0 NA NA 1 2 5 ENSG00000207431 0 NA NA NA NA 6 ENSG00000221312 0 1 2 3 2

and basically I’d like to get a…

How to: In R, what is the difference between the and [] notations for accessing the elements of a list?

In R, what is the difference between the [] and [[]] notations for accessing the elements of a list?

R provides two different methods for accessing the elements of a list or data.frame- the [] and [[]] operators.

What is the difference between the two? In what situations should I use one over the other?

Answer: In R, what is the difference between the [] and [[]] notations for accessing the…

Fixed How to join data frames in R (inner, outer, left, right)? #dev #it #asnwer

How to join data frames in R (inner, outer, left, right)?

Given two data frames

df1 = data.frame(CustomerId=c(1:6),Product=c(rep("Toaster",3),rep("Radio",3))) df2 = data.frame(CustomerId=c(2,4,6),State=c(rep("Alabama",2),rep("Ohio",1))) > df1 CustomerId Product 1 Toaster 2 Toaster 3 Toaster 4 Radio 5 Radio 6 Radio > df2 CustomerId State 2 Alabama 4 Alabama 6 Ohio

How can I do database style,…

Fixed How to sort a dataframe by column(s) in R #dev #it #asnwer

How to sort a dataframe by column(s) in R

I want to sort a data.frame by multiple columns in R. For example, with the data.frame below I would like to sort by column z (descending) then by column b (ascending):

dd <- data.frame(b = factor(c("Hi", "Med", "Hi", "Low"), levels = c("Low", "Med", "Hi"), ordered = TRUE), x = c("A", "D", "A", "C"), y = c(8, 3, 9, 9), z = c(1, 1, 1, 2)) dd b x y z 1 Hi…