R Datetime Lubridate – How to Convert Milliseconds to Minutes and Seconds

datetimelubridater

I want to convert milliseconds values in my data to minutes and seconds (in the format MM:SS e.g. a value of 1772094 should become 29:32).

The toy data looks like this:

df <- data.frame(
  ID = c("ID1", "ID2", "ID3"),
  duration = c(1723456, 1834537, 1945678)
)

The output I want is:

id	duration
ID1	28:43
ID2	30:35
ID3	32:26

I have gotten close but not perfect with the below code.

library(dplyr)
library(lubridate)
library(hms)

df2 <- df %>%
  mutate(duration_ms = seconds_to_period(duration/1000)) %>% 
  mutate(duration_ms = hms::hms(duration_ms))

I divide my millisecond values by a thousand to turn them into seconds so they can be used by the seconds_to_period() function in lubridate and then format them with hms.

But it's currently HH:MM:SS with the seconds having decimal places (not rounded).

How do I turn millisecond values into minutes and seconds values in the format MM:SS in R?

Best Answer

You can simply round() when you divide duration by 1000:

df %>%
    mutate(duration_ms = seconds_to_period(round(duration / 1000))) %>%
    mutate(duration_ms = hms::hms(duration_ms))

#    ID duration duration_ms
# 1 ID1  1723456    00:28:43
# 2 ID2  1834537    00:30:35
# 3 ID3  1945678    00:32:26

Note that rounding means that your second example, which is in fact 00:30:34.537 seconds, becomes 00:30:35. If you prefer to always round down you can use floor():

df %>%
    mutate(duration_ms = seconds_to_period(floor(duration / 1000))) %>%
    mutate(duration_ms = hms::hms(duration_ms))

#    ID duration duration_ms
# 1 ID1  1723456    00:28:43
# 2 ID2  1834537    00:30:34
# 3 ID3  1945678    00:32:25

Timestamp in milliseconds

To get the number of milliseconds since Unix epoch, call Date.now:

Date.now()

Alternatively, use the unary operator + to call Date.prototype.valueOf:

+ new Date()

Alternatively, call valueOf directly:

new Date().valueOf()

To support IE8 and earlier (see compatibility table), create a shim for Date.now:

if (!Date.now) {
    Date.now = function() { return new Date().getTime(); }
}

Alternatively, call getTime directly:

new Date().getTime()

Timestamp in seconds

To get the number of seconds since Unix epoch, i.e. Unix timestamp:

Math.floor(Date.now() / 1000)

Alternatively, using bitwise-or to floor is slightly faster, but also less readable and may break in the future (see explanations 1, 2):

Date.now() / 1000 | 0

Timestamp in milliseconds (higher resolution)

Use performance.now:

var isPerformanceSupported = (
    window.performance &&
    window.performance.now &&
    window.performance.timing &&
    window.performance.timing.navigationStart
);

var timeStampInMs = (
    isPerformanceSupported ?
    window.performance.now() +
    window.performance.timing.navigationStart :
    Date.now()
);

console.log(timeStampInMs, Date.now());

Python – Convert String ‘Jun 1 2005 1:33PM’ into Datetime

datetime.strptime parses an input string in the user-specified format into a timezone-naive datetime object:

>>> from datetime import datetime
>>> datetime.strptime('Jun 1 2005  1:33PM', '%b %d %Y %I:%M%p')
datetime.datetime(2005, 6, 1, 13, 33)

To obtain a date object using an existing datetime object, convert it using .date():

>>> datetime.strptime('Jun 1 2005', '%b %d %Y').date()
date(2005, 6, 1)

Links:

strptime docs: Python 2, Python 3
strptime/strftime format string docs: Python 2, Python 3
strftime.org format string cheatsheet

Notes:

strptime = "string parse time"
strftime = "string format time"

Best Answer

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Timestamp in milliseconds

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Python – Convert String ‘Jun 1 2005 1:33PM’ into Datetime

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