hmscalc 1.0.3

Add and subtract HH:MM[:SS] time strings in Python — durations, aggregation, and timedelta integration.

hmscalc

Add and subtract HH:MM / HH:MM:SS time strings in Python — no manual conversion to seconds required.

v1.0.0 is the first stable release with SemVer API guarantees.

Quick Start

pip install hmscalc

from hmscalc import HMSTime

a = HMSTime("1:30:15")
b = HMSTime("2:15:45")

print(a + b)   # "3:46:00"
print(a - b)   # "-0:45:30"
print(a * 2)   # "3:00:30"
print(a / 2)   # "0:45:07"

Why hmscalc?

Approach	Limitation
datetime.timedelta	No "1:30:15" string parsing out of the box
Manual seconds math	Verbose; easy to mishandle negative values
pytimeparse	Parse-only — arithmetic is still on you
hmscalc	Parse and add / subtract / aggregate in one API

Features

• Addition, subtraction, and scalar multiply/divide
• Sum, average, min, and max of multiple values
• HH:MM and HH:MM:SS input (hours may exceed 24 — duration model)
• Negative durations, comparison operators, datetime.timedelta integration
• Input whitespace trimming (" 1:30:15 ")
• Type hints with py.typed marker
• Python 3.9 through 3.14
• CLI: hmscalc add / sub / sum from the terminal

CLI

After pip install hmscalc:

hmscalc add 1:30 2:15 0:45
# 4:30:00

hmscalc sub 2:00 0:45
# 1:15:00

hmscalc sum 1:00 2:00 3:00
# 6:00:00

Equivalent: python -m hmscalc add 1:00 2:00

Usage

Import

from hmscalc import HMSTime

Creating HMSTime (string vs seconds vs timedelta)

Input	Recommended API	Example
"1:30:15" string	HMSTime("1:30:15")	Human-readable durations
Integer seconds	HMSTime.from_seconds(3661)	Programmatic / computed values
datetime.timedelta	HMSTime.from_timedelta(delta)	Interop with stdlib datetime

HMSTime(...) accepts strings only. Use from_seconds() for numeric seconds (TypeError if not int).

Basic Operations

a = HMSTime("1:30:15")
b = HMSTime("2:15:45")

print(a + b)            # "3:46:00"
print(a - b)            # "-0:45:30"
print(a > b)            # False
print(a.to_seconds())   # 5415
print(a.to_tuple())     # (1, 30, 15)
print(a.to_dict())      # {'hh': 1, 'mm': 30, 'ss': 15, 'negative': False}

Scalar Operations

HMSTime("1:00:00") * 3    # "3:00:00"
HMSTime("1:30:00") / 2    # "0:45:00"
2 * HMSTime("0:30:00")    # "1:00:00"

Aggregation

times = [HMSTime("1:30:15"), HMSTime("2:15:45"), HMSTime("0:45:30")]

HMSTime.sum(times)      # "4:31:30"
HMSTime.average(times)  # "1:30:30"
HMSTime.min(times)      # "0:45:30"
HMSTime.max(times)      # "2:15:45"

Work Time Example

work_sessions = [
    HMSTime("2:15:30"),
    HMSTime("1:45:00"),
    HMSTime("0:30:15"),
]
print(HMSTime.sum(work_sessions))  # "4:30:45"

timedelta Integration

import datetime

t = HMSTime("1:30:15")
delta = t.to_timedelta()
restored = HMSTime.from_timedelta(delta)  # HMSTime("1:30:15")

ISO 8601 Duration

t = HMSTime.from_iso8601("PT1H30M15S")
print(t.to_iso8601())  # "PT1H30M15S"
print(str(t))          # "1:30:15"

Time section only (PT…); date parts like P1D are not supported.

Custom Output Format

t = HMSTime("1:30:15")
t.format("HH:MM")     # "1:30"
t.format("HH:MM:SS")  # "1:30:15" — same as str(t)

Error Handling

from hmscalc import InvalidTimeFormatError, NotTimeStringError

HMSTime(" 1:30:15 ")   # OK — whitespace trimmed
HMSTime("1:99:00")     # InvalidTimeFormatError
HMSTime(123)             # NotTimeStringError

Negative Values

t = HMSTime("-1:00:00")
print(str(t))           # "-1:00:00"
print(t.is_negative)    # True
print(t.to_seconds())   # -3600
print(t.to_dict())      # {'hh': 1, 'mm': 0, 'ss': 0, 'negative': True}

to_tuple() returns absolute (hh, mm, ss); use is_negative or to_seconds() for sign.

Hashable (sets and dict keys)

a = HMSTime("1:00:00")
b = HMSTime("2:00:00")
sessions = {a, b, a}  # 2 unique items

API Reference

HMSTime(time_str: str)

Parse HH:MM or HH:MM:SS. Whitespace is trimmed. Hours may exceed 24 (duration model).

Class methods

Method	Description
HMSTime.from_seconds(total_seconds: int)	Build from integer seconds
HMSTime.from_timedelta(delta)	Build from datetime.timedelta
HMSTime.from_iso8601(duration)	Build from ISO 8601 PT… duration
HMSTime.sum(times)	Sum iterable; empty → "0:00:00"
HMSTime.average(times)	Mean, rounded to nearest second
HMSTime.min(times) / HMSTime.max(times)	Min / max of iterable

Instance methods & properties

Member	Description
is_negative	True if total seconds < 0
to_seconds()	Integer total seconds (signed)
to_minutes() / to_hours()	Float conversion
to_timedelta()	datetime.timedelta
to_iso8601()	ISO 8601 PT… string
format(fmt)	"HH:MM" or "HH:MM:SS" (__str__ = format("HH:MM:SS"))
to_tuple()	(hh, mm, ss) absolute components
to_dict()	{'hh', 'mm', 'ss', 'negative'}

Operators

+, -, *, / (scalar), ==, !=, <, <=, >, >=

Exceptions

from hmscalc import HMSTimeError, InvalidTimeFormatError, NotTimeStringError

Exception	When
InvalidTimeFormatError	Bad format, mm/ss ≥ 60, empty string
NotTimeStringError	Non-string input
HMSTimeError	Base class for both

Input Rules

• Formats: HH:MM or HH:MM:SS
• Minutes and seconds: 0–59
• Optional leading - for negative durations
• Surrounding whitespace is ignored
• Strict mode only: overflow minutes/seconds (e.g. 1:90:00) are rejected — see Input Policy

Development

See CONTRIBUTING.md for branching, CI, and release process.

poetry install
poetry run pytest --cov=hmscalc

Docker matrix (Python 3.9–3.14): docker build -t hmscalc . && docker run --rm hmscalc ./runtests.sh

Links

• PyPI
• Changelog
• Contributing
• Security policy
• API stability policy
• Migration guide
• Roadmap (v1.0.0)
• Zenn: v1.0.0 Stable リリース（下書き）
• Zenn: 作業時間を HH:MM で足し算する（チュートリアル） — 公開用下書き
• Zenn: PyPI 公開の記事

License

MIT License