CODEWITHSUNDEEP
r
dondapati
dondapati

Reputation: 849

Convert the each column of the dataframe in a list in to as.POSIXct

I have a list of dataframes i want convert in to each column of the dataframe in to time stamp

gg=list(a = data.frame(X1 = c(1516087622, 1516087622, 1516087622, 1516087622, 
1516087622), X2 = c(1516087622, 1516087622, 1516087622, 1516087622, 
1516087622)),b = data.frame(X1 = c(1516078740, 1516078740, 1516078740, 1516078740, 
1516078740), X2 = c(1516078740, 1516078740, 1516078740, 1516078740, 
1516078740)))

> gg
$a
          X1         X2
1 1516087622 1516087622
2 1516087622 1516087622
3 1516087622 1516087622
4 1516087622 1516087622
5 1516087622 1516087622

$b
          X1         X2
1 1516078740 1516078740
2 1516078740 1516078740
3 1516078740 1516078740
4 1516078740 1516078740
5 1516078740 1516078740

I am using the following function 

Map(as.POSIXct,lapply(gg,function(x) x[[1]]),origin = "1970-01-01")

it's convert the first column of the each dataframe but i want convert all at a time ..

I need base R function.

Thank you.

Upvotes: 1

Views: 190

Answers (1)

akrun
akrun

Reputation: 887088

Here is one option with tidyverse. We map through the list elements and with mutate_all change all the columns to POSIXct class

library(dplyr)
library(purrr)
map(gg, ~ .x %>% 
            mutate_all(funs(as.POSIXct(., origin = "1970-01-01"))))
#$a
#                   X1                  X2
#1 2018-01-16 12:57:02 2018-01-16 12:57:02
#2 2018-01-16 12:57:02 2018-01-16 12:57:02
#3 2018-01-16 12:57:02 2018-01-16 12:57:02
#4 2018-01-16 12:57:02 2018-01-16 12:57:02
#5 2018-01-16 12:57:02 2018-01-16 12:57:02

#$b
#                   X1                  X2
#1 2018-01-16 10:29:00 2018-01-16 10:29:00
#2 2018-01-16 10:29:00 2018-01-16 10:29:00
#3 2018-01-16 10:29:00 2018-01-16 10:29:00
#4 2018-01-16 10:29:00 2018-01-16 10:29:00
#5 2018-01-16 10:29:00 2018-01-16 10:29:00

The corresponding base R option would be to loop through the list elements with Map, then loop through each column of the dataset with lapply and assign the transformed value to the dataset (x[] <-), return the dataset 

Map(function(x) {x[] <- lapply(x, as.POSIXct, origin = "1970-01-01");x }, gg)

Upvotes: 1

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