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rchron

Strange error while converting minutes to hours


I was using the command below to convert minutes (e.g. 366) to hours and minutes format (e.g. 6:06) when I came across a strange error:

library(chron) #https://cran.r-project.org/web/packages/chron/chron.pdf

sub(":\\d{2}", "", times((X%/%60 +  X%%60 /3600)/24))

I assign a vector in the place of X in the actual code, for now I will just use a number. For example:

sub(":\\d{2}", "", times((240.8%/%60 +  240.8%%60 /3600)/24))

Yields "04:01" as it should be. However, the same command with 419.8 minutes wrongly gives "6:00"?

sub(":\\d{2}", "", times((419.8%/%60 +  419.8%%60 /3600)/24))

When I re-run it without the digit, 419, it is correct again. "06:59". I re-ran the code with random numbers and it seems to be doing fine with others. I can't understand the problem. What am I doing wrong?


Solution

  • library(chron)
    times((419.8%/%60 +  419.8%%60 /3600)/24)
    # [1] 06:01:00
    times((419%/%60 +  419%%60 /3600)/24)
    # [1] 06:00:59
    

    The problem is in your sub regex. Try:

    sub(":\\d{2}$", "", times((419%/%60 +  419%%60 /3600)/24))
    # [1] "06:00"
    sub(":\\d{2}$", "", times((419.8%/%60 +  419.8%%60 /3600)/24))
    # [1] "06:01"
    

    Update:

    Additionally, your math is incorrectly converting minutes to seconds. Try:

    times((419.8%/%60 +  419.8%%60 / 60)/24)
    # [1] 06:59:48
    sub(":\\d{2}$", "", times((419.8%/%60 +  419.8%%60 / 60)/24))
    # [1] "06:59"