kimshin.py

from datetime import datetime, timedelta

# google
google_diff = datetime(2013, 7, 7) - datetime(2012, 7, 8) + timedelta(1)
google_years = google_diff.days / 365

# vingle
vingle_diff = datetime(2018, 5, 27) - datetime(2016, 3, 2) + timedelta(1)
vingle_years = vingle_diff.days / 365

# toss, see https://toss.im/career-2021
toss_start_dt = datetime(2018, 5, 28)
current_dt = datetime.now()
toss_diff = current_dt - toss_start_dt + timedelta(1)

toss_half_year_count = toss_diff.days / (365 / 2)

toss_start_years = toss_half_year_count * 2
toss_end_years = toss_half_year_count * 3

# total
start = round(toss_start_years + vingle_years + google_years, 2)
end = round(toss_end_years + vingle_years + google_years, 2)

print(
    f"""
# google
2012.7.8 ~ 2013.7.7: {round(google_years, 2)} years ({google_diff.days} days)
# vingle
2016.3.2 ~ 2018.5.27: {round(vingle_years, 2)} years ({vingle_diff.days} days)
# toss
2018.5.28 ~ current: {round(toss_diff.days / 365, 2)} years ({toss_diff.days} days)
> 6개월마다 2 ~ 3년 성장률 적용: {toss_diff.days}일 ÷ 180일 = {round(toss_half_year_count, 2)}회 성장
> 추가 경력: [{round(toss_half_year_count, 2)} × 2년, {round(toss_half_year_count, 2)} × 3년] = [{round(toss_start_years, 2)}년, {round(toss_end_years, 2)}년]
---
∴ 김신은 {start} ~ {end}년차 개발자다.
""".strip()
)