How can I change "m" into "mm" for my dates?-CodePudding

Assume I have data in a CSV that I've imported in R. This is a simplified version- the real sheet has 4700 rows. There are months in 1 digits and there are months in 2 digits.

| | Posted.On |

|1| 5/18/2022 |

|2| 07/04/2022|

|3| 6/20/2022 |

I would like to change all months in 1 digits to 2 digits (e.g. 5/18/2022 to 05/18/2022). How can I do this?

CodePudding user response：

This sould be enough:

    tibble(date = c('5/18/2022', '12/04/2022', '6/20/2022', '1/20/2022')) %>% 
  mutate(month = str_extract(date, '\\d '),
         date = if_else(str_length(month) == 1  , paste0('0',date), date)) %>%
  select(-month)

# # A tibble: 4 × 1
# date      
# <chr>     
# 1 05/18/2022
# 2 12/04/2022
# 3 06/20/2022
# 4 01/20/2022

CodePudding user response：

gsub() can replace a single digit before the first / with a zero-filled digit:

 Posted.On <- c('5/18/2022', '07/04/2022', '6/20/2022')

 want <- gsub('^(\\d{1}/)','0\\1', Posted.On)