15-03-2019

docs/Programmation/Python/date.md

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+# Date
+
+
+
+On importe le module `datetime`.
+
+```python
+from datetime import datetime
+```
+
+Obtenir l'heure courante:
+
+```python
+>>> maintenant = datetime.now()
+>>> maintenant
+datetime.datetime(2019, 3, 2, 6, 57, 24, 532139)
+
+# datetime(année, mois, jour, heure, minute, seconde, microseconde, fuseau horaire)
+
+>>> maintenant.year
+2019
+>>> maintenant.month
+3
+>>> maintenant.day
+2
+>>> maintenant.hour
+6
+>>> maintenant.minute
+57
+>>> maintenant.second
+24
+>>> maintenant.microsecond
+532139
+>>> maintenant.isocalendar
+<built-in method isocalendar of datetime.datetime object at 0x104900b70>
+
+>>> maintenant.date()
+datetime.date(2019, 3, 2)
+>>> maintenant.time()
+datetime.time(6, 57, 24, 532139)
+```
+
+Créer une date:
+
+```python
+# année, mois, jour sont obligatoires
+>>> a = datetime(2001, 1, 1)
+>>> a.year
+2001
+```
+
+Durée:
+
+```python
+>>> duree = datetime.now() - datetime(2001, 1, 1)
+>>> duree
+datetime.timedelta(days=6634, seconds=26875, microseconds=353545)
+
+>>> duree.days
+6634
+>>> duree.total_seconds()
+573204475.353545
+
+```
+
+Format d'affichage:
+
+```python
+>>> maintenant = datetime.now()
+>>> maintenant
+datetime.datetime(2019, 3, 2, 7, 50, 30, 756453)
+
+>>> maintenant_US = datetime.now().strftime('%Y-%m-%d %H:%M:%S.%f')
+>>> maintenant_US
+'2019-03-02 07:49:12.627321'
+
+>>> maintenant_FR = datetime.now().strftime('%d-%m-%Y %H:%M:%S')
+>>> maintenant_FR
+'02-03-2019 07:53:05'
+```
+
+[Liste des formats](https://docs.python.org/fr/3/library/datetime.html#strftime-and-strptime-behavior)
+
+### Calendrier:
+
+```python
+>>> import calendar
+```
+
+```python
+>>> calendar.mdays	# nb de. jours dans le mois
+[0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
+>>> calendar.isleap(2020)	# année bisextile ?
+True
+>>> calendar.weekday(1966, 8, 31)	# jour précis d'une date (2 => mercredi)
+2
+```
+
+
+
+### Timestamp:
+
+Récupérer le timestamp courant:
+
+```python
+>>> from datetime import datetime
+>>> import calendar
+>>> d = datetime.now()
+>>> ts = calendar.timegm(d.utctimetuple())
+>>> ts
+1551516334
+```
+
+```python
+>>> import time
+>>> ts = time.time()
+>>> ts
+1551511030.9611452
+```
+
+```python
+>>> import datetime
+>>> ts = datetime.datetime.now().timestamp()
+>>> ts
+1551511138.821511
+
+# equivalent
+>>> from datetime import datetime
+>>> ts = datetime.now().timestamp()
+>>> ts
+1551511979.337509
+```
+
+```python
+import calendar, time
+>>> ts = calendar.timegm(time.gmtime())
+>>> ts
+1551511394
+```
+
+Récupérer une date depuis un timestamp:
+
+```python
+# heure utc
+>>> d = datetime.utcfromtimestamp(ts)
+>>> d
+datetime.datetime(2019, 3, 2, 8, 53, 3)
+```
+
+```python
+# heure LOCALE
+>>> e = datetime.fromtimestamp(ts)
+>>> e
+datetime.datetime(2019, 3, 2, 9, 53, 3)
+```
+