A util to get a number of seconds from a (flexible) string description of a duration using day, hour, minutes, and seconds units.

str_2_seconds_duration.py

import time
import re

p = re.compile('[\d\.]+')

seconds_for_unit = {
    'd': 60 * 60 * 24,
    'h': 60 * 60,
    'm': 60,
    's': 1
}


def time_spec_to_seconds(time_spec: str) -> float:
    """A flexible way to get a time (duration) in seconds, from a string.
    How flexible? Well, the string needs to interleave numbers and words, and the first letter of the word needs
    to be d (day), h (hour), m (minute), or s (second). The function will ignore the rest.

    Args:
        time_spec: The string specifying the time

    Returns: A duration, float, in seconds.

    >>> assert time_spec_to_seconds('5 minutes') == 300.0
    >>> assert time_spec_to_seconds('1heure 1mn 1 secondi') == 3600 + 60 + 1  # only the first letter of the unit counts
    >>> assert time_spec_to_seconds('72m109.7s') == 4429.7  # numbers don't have a limit and can use decimals
    >>> assert time_spec_to_seconds('3h 12mn42 seconds') == 11562.0
    """
    requested_time = None
    keys = list(map(str.strip, p.split(time_spec)))
    vals = list(map(float, p.findall(time_spec)))
    if keys[0] == '':
        keys = keys[1:]
    if len(keys) >= 1 and len(vals) >= 1:
        duration_spec = list(zip(vals, keys))
        requested_time = 0
        for val, unit in duration_spec:
            seconds_to_add = val * seconds_for_unit.get(unit[0], None)
            if seconds_to_add is None:
                raise ValueError(
                    f"Malformated time string (should use units d, h, m, and s): {time_spec}")
            requested_time += seconds_to_add
    return requested_time


def now_minus_spec_to_utc_seconds(now_minus_spec: str) -> float:
    """Get the UTC time of now minus some duration.
    Input must start with a dash (that is, the minus symbol "-") and then describe a duration,
    with days, hours, minutes, and/or seconds.

    Args:
        now_minus_spec: A string starting with "-" and then interleaving numbers and time units

    Returns: A UTC seconds float

    Examples:
        now_minus_spec_to_utc_seconds('- 1 hour 2 mn 43s')
    """
    assert now_minus_spec.startswith('-'), "String should start with '-'"
    return time.time() - time_spec_to_seconds(now_minus_spec[1:])