1. datetime module
1.1 Main modules
datetime.date() #processing date (year, month, day) datetime.time() #processing time (hour, minute, second and millisecond) datetime.datetime() #processing date + time datetime.timedelta() #processing period (time interval)
#获取今天的时间
print(datetime.date.today())
print(datetime.datetime.now())
print(datetime.date.today().strftime("%Y-%m-%d %H-%M-%S"))
print(datetime.datetime.now().isoformat())
1.2 Timestamp
The timestamp refers to the total number of seconds from January 01, 1970, 00:00:00 GMT to the present.
1.2.1 Converting Dates to Timestamps and Timestamps to Dates
timetuple function: convert date to struct_time format
time.mktime function: Returns a floating-point number representing the time in seconds
import datetime,time
today = datetime.date.today()
print(today.timetuple())
print(time.mktime(today.timetuple()))
print(datetime.date.fromtimestamp(1668614400.0))
1.2.2 Addition and subtraction in time
The timedelta() method represents the interval between two time points
import datetime
today = datetime.datetime.now()
print(today)
yesterday = today - datetime.timedelta(days=1)
print(yesterday)
hours = today - datetime.timedelta(hours=1)
print(hours)
2. Calendar module
Several functions and classes related to the calendar can generate a calendar in text form.
2.1 Common functions
import calendar calendar.calendar(<year>) calendar.month(<year>,<month>) #return multi-line string calendar.prmonth(<year>,<month>) #equivalent to print(calendar.month(< Year>,<month>)) calendar.prcal(<year>) #equivalent to print(calendar.calendar(<year>))
import calendar
print(calendar.month(2022,11))
print(calendar.calendar(2022))The output shows:
E:\ProgramData\Anaconda3\python.exe C:/Users/dl/PycharmProjects/MyProjects/1.py
November 2022
Mo Tu We Th Fr Sa Su
1 2 3 4 5 6
7 8 9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30
2022
January February March
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 1 2 3 4 5 6 1 2 3 4 5 6
3 4 5 6 7 8 9 7 8 9 10 11 12 13 7 8 9 10 11 12 13
10 11 12 13 14 15 16 14 15 16 17 18 19 20 14 15 16 17 18 19 20
17 18 19 20 21 22 23 21 22 23 24 25 26 27 21 22 23 24 25 26 27
24 25 26 27 28 29 30 28 28 29 30 31
31
April May June
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 3 1 1 2 3 4 5
4 5 6 7 8 9 10 2 3 4 5 6 7 8 6 7 8 9 10 11 12
11 12 13 14 15 16 17 9 10 11 12 13 14 15 13 14 15 16 17 18 19
18 19 20 21 22 23 24 16 17 18 19 20 21 22 20 21 22 23 24 25 26
25 26 27 28 29 30 23 24 25 26 27 28 29 27 28 29 30
30 31
July August September
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 3 1 2 3 4 5 6 7 1 2 3 4
4 5 6 7 8 9 10 8 9 10 11 12 13 14 5 6 7 8 9 10 11
11 12 13 14 15 16 17 15 16 17 18 19 20 21 12 13 14 15 16 17 18
18 19 20 21 22 23 24 22 23 24 25 26 27 28 19 20 21 22 23 24 25
25 26 27 28 29 30 31 29 30 31 26 27 28 29 30
October November December
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 1 2 3 4 5 6 1 2 3 4
3 4 5 6 7 8 9 7 8 9 10 11 12 13 5 6 7 8 9 10 11
10 11 12 13 14 15 16 14 15 16 17 18 19 20 12 13 14 15 16 17 18
17 18 19 20 21 22 23 21 22 23 24 25 26 27 19 20 21 22 23 24 25
24 25 26 27 28 29 30 28 29 30 26 27 28 29 30 312.2 List the calendar
calendar.monthcalendar()
Returns a calendar of a certain month in a certain year, which is a nested list. The innermost list contains seven elements representing a week (Monday to Sunday). 0 if there is no day of the month.
import calendar
print(calendar.monthcalendar(2022,11))
输出结果：
[[0, 1, 2, 3, 4, 5, 6], [7, 8, 9, 10, 11, 12, 13], [14, 15, 16, 17, 18, 19, 20], [21, 22, 23, 24, 25, 26, 27], [28, 29, 30, 0, 0, 0, 0]]2.3 Judging leap year
calendar.isleap(<年>)
import calendar
print(calendar.isleap(2022))
print(calendar.isleap(2000))
输出结果：
False
True2.4 Judging the number of months and days of the week
When calculating the day of the week for a certain month, when there are a total of days, it starts from 0, Monday, Tuesday...
When calculating the day of the week, 0-6 is returned, corresponding to Monday to Sunday.
import calendar
print(calendar.monthrange(2022,11))
print(calendar.weekday(2022,11,18))
输出结果：
(1, 30)
4Three, time module
3.1 Get timestamp
time.time() method
Calculate the running time of a program
import time
t1 = time.time()
a = 0
for i in range(10000):
a += i
print(a)
t2 = time.time()
print(t2-t1)
3.2 Get date format
3.2.1 Get the current time
import time
t1 = time.asctime()
t2 = time.ctime()
print(t1)
print(t2)
3.2.2 Convert tuple data to date
import time
t = (2022,11,18,11,8,30,0,0,0)
print(time.asctime(t))
输出结果：
Mon Nov 18 11:08:30 20223.3 Use the index to obtain time information
import time
print(time.localtime())
t = time.localtime()
year = t[0]
print(year)
4. Arithmetic module
4.1 random module
Pseudo-random number: The random function in the computer is simulated according to a certain algorithm, and the result is deterministic and predictable.
Random number seed: The random number seed is the same, and the random number sequence is also the same.
random.seed(a = None)
random() #Generate a random real number in the range [0,1)
uniform() #Generate a random floating point number within the specified range
randint(m,n) #Generate an integer within the specified range [m,n]
randrange(a,b,n) #You can randomly select a number from the set increasing by n within the range of [a,b)
getrandbits(k) #Generate k-bit binary random integers
choice() # Randomly select an element from the specified sequence
sample() #can specify the number of random elements each time
shuffle() # Randomly sort all elements in the variable sequence
import random
colors = ['red','green','blue','yellow','black']
print(random.choice(colors))
print(random.sample(colors,3))
random.shuffle(colors)
print(colors)
输出结果：
black
['black', 'blue', 'green']
['red', 'blue', 'green', 'yellow', 'black']5. File text reading and writing module
5.1 Opening of files
open() function:
f = open(filename[,mode[,buffering]])
f: the file object returned by open()
filename: the string name of the file
mode: optional parameter, open mode and file type
buffering: optional parameter, the buffer of the file, the default is -1
Open mode of the file:
The first letter of mode indicates the operation on it:
'r': indicates read mode
'w': Indicates write mode
'x': Indicates that the file is newly created and written if the file does not exist
'a': Indicates that the content is appended at the end of the file
'+': Indicates read and write mode
The second letter of mode is the file type:
't': Indicates text type
'b': indicates a binary file
5.2 Reading, writing and accessing files
File write operations:
f.write(str)
f.writelines(strlist): write a list of strings
File read operation:
f.read()
f.readline(): returns a line
f.readlines(): return all lines, list
f = open('mytxt','w')
f.writelines(['apple\n','orange\n'])
f.close()
f = open('mytxt','r')
print(f.readlines())
f.close()
After opening the file, you must remember to close it. The function of closing is to terminate the connection to the external file and refresh the data in the cache area to the hard disk at the same time.
5.3 Structured text files: CSV
File reading—reader
re = csv.reader()
Accepts an iterable object (such as a csv file) and returns a generator from which the content can be parsed.
File reading—DictReader
Similar to the reader, it is suitable for csv files with headers, and each returned cell is placed in a tuple value.
File write operation:
w = csv.writer()w.writerow(rows)
When the file does not exist, it is automatically generated, supporting single-line writing and multi-line writing
Dictionary data is written:
w = csv.DictWriter()
w.writeheader()
w.writerow(rows)