Smooth python and cookbook learning notes (5), pythoncookbook

Smooth python and cookbook learning notes (5), pythoncookbook
1. Random selection

Use the random module to generate random numbers in python.

1. Randomly select elements from the sequence and use random. choice ()

>>> import random>>> values = [1, 2, 3, 4, 5, 6]>>> random.choice(values)3>>> random.choice(values)3>>> random.choice(values)1>>> random.choice(values)1>>> random.choice(values)4

2. Retrieve the specified number of elements and use random. sample ()

>>> random.sample(values, 2)[1, 4]>>> random.sample(values, 2)[3, 5]>>> random.sample(values, 3)[5, 3, 2]>>> random.sample(values, 3)[1, 3, 2]

3. Disrupt the sequence, which can be used for shuffling. Use random. shuffle ()

>>> random.shuffle(values)>>> values[2, 4, 5, 3, 6, 1]>>> random.shuffle(values)>>> values[2, 6, 5, 4, 3, 1]

4. Generate a random integer using random. randint ()

>>> random.randint(1, 10)3>>> random.randint(1, 10)10>>> random.randint(1, 10)5

5. Generate a floating point number between 0 and 1 using random. random ()

>>> random.random()0.31720220264500265>>> random.random()0.8230452349376671>>> random.random()0.09307172325744872

6. generate random bitwise integers using random. getrandbits ()

>>> random.getrandbits(200)859899606181938256764615251875627706548045135119258688489931>>> random.getrandbits(200)582401031226834278134883678914218487507678688169321631685078

 

2. Time Conversion

1. Use the datetime module in python to convert the time.

>>> from datetime import timedelta>>> a = timedelta(days = 2, hours = 6)>>> b = timedelta(hours = 4.5)>>> c = a + b>>> c.days2>>> c.seconds37800>>> c.seconds / 360010.5>>> c.total_seconds() / 360058.5

Indicates a specific date and time.

>>> from datetime import datetime>>> a = datetime(2017, 9, 8)>>> print(a + timedelta(days=2))2017-09-10 00:00:00>>> b = datetime(2017, 9, 22)>>> d = b - a>>> d.days14>>> now = datetime.today()>>> print(now)2017-09-08 20:09:56.904169>>> print(now + timedelta(minutes=10))2017-09-08 20:19:56.904169

2. Use the dateutil module to process the days in different months. Datetime cannot process the month.

>>> from dateutil.relativedelta import relativedelta>>> a = datetime(2017, 9, 8)>>> a + relativedelta(months=1)datetime.datetime(2017, 10, 8, 0, 0)>>> a + relativedelta(months=4)datetime.datetime(2018, 1, 8, 0, 0)
>>> b = datetime(2017, 11, 11)>>> d = b - a>>> ddatetime.timedelta(64)
>>> d = relativedelta(b, a)>>> drelativedelta(months=+2, days=+3)>>> d.months2>>> d.days3

3. Convert the string to time, use datetime. strptime (), and convert the time to the string using datetime. strftime ()

>>> from datetime import datetime>>> text = '2017-9-8'>>> y = datetime.strptime(text, '%Y-%m-%d')>>> z = datetime.now()>>> diff = z - y>>> diffdatetime.timedelta(0, 73494, 826144)>>> ydatetime.datetime(2017, 9, 8, 0, 0)>>> zdatetime.datetime(2017, 9, 8, 20, 24, 54, 826144)>>> nice_z = datetime.strftime(z, '%A %B %d %Y')>>> nice_z'Friday September 08 2017'