CODEWITHSUNDEEP
rdateformat
user9259005
user9259005

Reputation: 475

changing date format with only months and year

I have a column with dates that are formatted like this:

yyyymm (e.g. 201809)

I want them to be formatted like this:

mm.yyyy (e.g. 09.2018)

I tried: 

FF5factors$date <- strptime(FF5factors$date, format= "%Y%m")
format(FF5factors$date, format="%m.%Y")

But it only returns NA values.

Upvotes: 0

Views: 1152

Answers (2)

G. Grothendieck
G. Grothendieck

Reputation: 269431

Here are some alternatives. The question did not provide date in reproducible form so we assume the first line below although the first 4 alternatives will also work with date <- "201809" and with date <- factor(201809) .

date <- 201809

# 1
sub("(....)(..)", "\\2.\\1", date)
## [1] "09.2018"

# 2
library(zoo)
format(as.yearmon(format(date), "%Y%m"), "%m.%Y")
## [1] "09.2018"

# 3
paste(substr(date, 5, 6), substr(date, 1, 4), sep = ".")
## [1] "09.2018"

# 4
format(as.Date(paste0(date, "01"), "%Y%m%d"), "%m.%Y")
## [1] "09.2018"

# 5
sprintf("%02d.%d", date %% 100, date %/%100)
## [1] "09.2018"

Upvotes: 2

s__
s__

Reputation: 9485

What about:

d <- '201809'
format(as.Date(d,'%Y%M'),'%m.%Y')
[1] "09.2018"

Upvotes: 3

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