Fluent Python and Cookbook Learning Notes (v)

1. Random Selection

Generate random numbers in Python using the random module.

1. Randomly select elements from the sequence, using 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. Remove the specified number of elements, using 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. Sequence of scrambled sequences, can be used to shuffle, 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 random integers, using random.randint ()

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

5. Generate floating-point numbers between 0 and 1 using random.random ()

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

6. Generate random bits of integers, using random.getrandbits ()

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

2. Conversion of Time

The datetime module is used in 1.python to convert the time.

 from 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

Represents a specific date and time.

 from Import datetime>>> a = DateTime (9, 8)print(A + timedelta (days=2)) 2017-09-10 00:00:00>>> B = DateTime (9, a)>>> d = B- a>>> d.days
    14>>> now = datetime.today ()print(now)print(now + timedelta ( minutes=10))2017-09-08 20:19:56.904169

2. Using the Dateutil module, you can handle the number of days in different months. DateTime cannot process months.

>>> fromDateutil.relativedeltaImportRelativedelta>>> 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 string to time, use Datetime.strptime (), convert time to string using Datetime.strftime ()

>>> fromDatetimeImportdatetime>>> 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'

Fluent Python and Cookbook Learning Notes (v)