Using R Convert Data.Frame to Simple Vector

Using R convert data.frame to simple vector

see ?unlist

Given a list structure x, unlist simplifies it to produce a vector
which contains all the atomic components which occur in x.

unlist(v.row)
[1] 177 165 177 177 177 177 145 132 126 132 132 132 126 120 145 167 167 167
       167 165 177 177 177 177

EDIT

You can do it with as.vector also, but you need to provide the correct mode:

 as.vector(v.row,mode='numeric')
 [1] 177 165 177 177 177 177 145 132 126 132 132 132 126 120 145 167 167
      167 167 165 177 177 177 177

Convert data.frame column to a vector?

I'm going to attempt to explain this without making any mistakes, but I'm betting this will attract a clarification or two in the comments.

A data frame is a list. When you subset a data frame using the name of a column and [, what you're getting is a sublist (or a sub data frame). If you want the actual atomic column, you could use [[, or somewhat confusingly (to me) you could do aframe[,2] which returns a vector, not a sublist.

So try running this sequence and maybe things will be clearer:

avector <- as.vector(aframe['a2'])
class(avector) 

avector <- aframe[['a2']]
class(avector)

avector <- aframe[,2]
class(avector)

Convert data frame into vector

Basically, data frames are lists, so that you can invoke unlist(df).

Convert a dataframe to a vector (by rows)

You can try as.vector(t(test)). Please note that, if you want to do it by columns you should use unlist(test).

Convert a row of a data frame to vector

When you extract a single row from a data frame you get a one-row data frame. Convert it to a numeric vector:

as.numeric(df[1,])

As @Roland suggests, unlist(df[1,]) will convert the one-row data frame to a numeric vector without dropping the names. Therefore unname(unlist(df[1,])) is another, slightly more explicit way to get to the same result.

As @Josh comments below, if you have a not-completely-numeric (alphabetic, factor, mixed ...) data frame, you need as.character(df[1,]) instead.

convert a row of a data frame to a simple vector in R

Example from mtcars data

mydata<-mtcars
k<-mydata[1,]
          mpg cyl disp  hp drat   wt  qsec vs am gear carb
Mazda RX4  21   6  160 110  3.9 2.62 16.46  0  1    4    4
names(k)<-NULL

unlist(c(k))
 [1]  21.00   6.00 160.00 110.00   3.90   2.62  16.46   0.00   1.00   4.00   4.00

Updated as per @Ananda: unlist(mydata[1, ], use.names = FALSE)

Convert dataframe into named vectors based on column names

You could do something like this (though @MartinGal gives a better method). We can convert each column to a list, then flatten to just have a named vector, then can save to the global environment.

library(tidyverse)

list2env(flatten(apply(df, 2, function(x) as.list(x))), envir = .GlobalEnv)

Convert entire data frame into one long column (vector)

The mysterious operation you are looking for is called unlist:

> df <- data.frame(C1=c(1,NA,3),C2=c(4,5,NA),C3=c(NA,8,9))
> unlist(df, use.names = F)
[1]  1 NA  3  4  5 NA NA  8  9

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