Convert time string expressed as <number>[m|h|d|s|w] to seconds in Python

Question

Is there a good method to convert a string representing time in the format of [m|h|d|s|w] (m= minutes, h=hours, d=days, s=seconds w=week) to number of seconds? I.e.

def convert_to_seconds(timeduration):
    ...

convert_to_seconds("1h")
-> 3600

convert_to_seconds("1d")
-> 86400

etc?

Thanks!

Answer 1

Yes, there is a good simple method that you can use in most languages without having to read the manual for a datetime library. This method can also be extrapolated to ounces/pounds/tons etc etc:

seconds_per_unit = {"s": 1, "m": 60, "h": 3600, "d": 86400, "w": 604800}

def convert_to_seconds(s):
    return int(s[:-1]) * seconds_per_unit[s[-1]]

Answer 2

I recommend using the timedelta class from the datetime module:

from datetime import timedelta

UNITS = {"s":"seconds", "m":"minutes", "h":"hours", "d":"days", "w":"weeks"}

def convert_to_seconds(s):
    count = int(s[:-1])
    unit = UNITS[ s[-1] ]
    td = timedelta(**{unit: count})
    return td.seconds + 60 * 60 * 24 * td.days

Internally, timedelta objects store everything as microseconds, seconds, and days. So while you can give it parameters in units like milliseconds or months or years, in the end you'll have to take the timedelta you created and convert back to seconds.

In case the ** syntax confuses you, it's the Python apply syntax. Basically, these function calls are all equivalent:

def f(x, y): pass

f(5, 6)
f(x=5, y=6)
f(y=6, x=5)

d = {"x": 5, "y": 6}
f(**d)

Answer 3

And another to add to the mix. This solution is brief, but fairly tolerant, and allows for multiples, such as 10m 30s

from datetime import timedelta
import re

UNITS = {'s':'seconds', 'm':'minutes', 'h':'hours', 'd':'days', 'w':'weeks'}

def convert_to_seconds(s):
    return int(timedelta(**{
        UNITS.get(m.group('unit').lower(), 'seconds'): float(m.group('val'))
        for m in re.finditer(r'(?P<val>\d+(\.\d+)?)(?P<unit>[smhdw]?)', s, flags=re.I)
    }).total_seconds())

Test results:

>>> convert_to_seconds('10s')
10
>>> convert_to_seconds('1')  # defaults to seconds
1
>>> convert_to_seconds('1m 10s')  # chaining
70
>>> convert_to_seconds('1M10S')  # case insensitive
70
>>> convert_to_seconds('1week 3days')  # ignores 'eek' and 'ays'
864000
>>> convert_to_seconds('This will take 1.25min, probably.')  # floats
75

not perfect

>>> convert_to_seconds('1month 3days')  # actually 1minute + 3 days
259260
>>> convert_to_seconds('40s 10s')  # 1st value clobbered by 2nd
10

Answer 4

I usually need to support raw numbers, string numbers and string numbers ending in [m|h|d|s|w].

This version will handle: 10, "10", "10s", "10m", "10h", "10d", "10w".

Hat tip to @Eli Courtwright's answer on the string conversion.

UNITS = {"s":"seconds", "m":"minutes", "h":"hours", "d":"days", "w":"weeks"}

def convert_to_seconds(s):
    if isinstance(s, int):
        # We are dealing with a raw number
        return s

    try:
        seconds = int(s)
        # We are dealing with an integer string
        return seconds
    except ValueError:
        # We are dealing with some other string or type
        pass

    # Expecting a string ending in [m|h|d|s|w]
    count = int(s[:-1])
    unit = UNITS[ s[-1] ]
    td = timedelta(**{unit: count})
    return td.seconds + 60 * 60 * 24 * td.days