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Tibble

Hello! I am trying to change the Start.time variable from the character format of "4:00 PM" and take out the PM/AM and leave it as 4:00 as a numerical variable if possible. Thanks!

Vkara
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  • [See here](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) on making an R question that folks can help with. That includes a sample of data (not a picture of it), all necessary code, and a clear explanation of what hasn't worked. – camille Sep 20 '19 at 18:06

2 Answers2

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One option is to use str_remove to match zero or more space (\\s*) followed by the letters 'A', 'P', 'M' at the end ($) of the string 

library(stringr)
library(dplyr)
df1 %>%
     mutate(Start.time = str_remove(Start.time, "\\s*[APM]+$"))

In base R, this can be done with sub

df1$Start.time <- sub("\\s*[APM]+$", "", df1$Start.time)

Or with substr

trimws(substr(df1$Start.time, 1, 5))
akrun
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gsub("\\s*[APM]", "", start.time) can be used to replace the string part after HH:MM with an empty string, leaving only the HH:MM bit.

trimws(x) replaces any leading whitespace in the string x. 

> start.time
[1] "4:00 PM"  "12:00 AM" " 4:00 AM"

> trimws(gsub("\\s*[APM]", "", start.time))
[1] "4:00"  "12:00" "4:00"
Ben Wynne-Morris
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  • May I request you to please add some more context around your answer. Code-only answers are difficult to understand. It will help the asker and future readers both if you can add more information in your post. See also [Explaining entirely code-based answers](https://meta.stackexchange.com/questions/114762/explaining-entirely-code-based-answers). – help-info.de Sep 21 '19 at 16:29