python学习笔记（二）：基础知识点

python基本元素

7 // 2

7 % 3

# 取商以及余数
divmod(7,3)

(2, 1)

1j*1j

(-1+0j)

10/3

3.3333333333333335

'3,''1.00e2'

'3,1.00e2'

'3,' + '1.00e2'

'3,1.00e2'

'na'*3

'nanana'

'na'[0:1]

'n'

w = ''
if w:
    print("hh")
else:
    print("hhh")

hhh

count = 1
while count <=5:
    print(count)
    count += 1

while True:
    stuff = input('string to capitalize[type q to quit]: ')
    if stuff == "q":
        break
    print(stuff.capitalize())

string to capitalize[type q to quit]: q

不能将可变的数据类型当作函数的参数值

字符串处理

import unicodedata
name = unicodedata.name('u2603')
value = unicodedata.lookup(name)
value

'☃'

place = 'cafu00e9'
place

'café'

place = 'N{LATIN SMALL LETTER E WITH ACUTE}'
a = place.encode('utf-8') # 编码
a

b'xc3xa9'

b = a.decode('utf-8') # 解码
b

'é'

'%d%%' % 32

'32%'

import re
source = "￥马冬梅.com"
m = re.search(r'w*', source)
m.group()

''

import string
pri = string.printable
re.findall('/.', pri)

['/:']

import re
source = "<b>frf<b>"
m = re.findall(r'<.+>', source)
m

['<b>frf<b>']

pome = '''thewrj ok poj 'po 
jio lkn 
;jij 
j; %%javascriptjoij 
j;oi joijl 
jiojioj;oij
'''
len(pome)

fout = open('datas', 'wt')
fout.write(pome)

fout.close()

fin = open('datas', 'r')
pomes = fin.read()
fin.close()
pomes

"thewrj ok poj 'po 
jio lkn 
;jij 
j; %%javascriptjoij 
j;oi joijl 
jiojioj;oij
"

fout = open('oops.txt', 'wt')
print('hollow word!', file = fout)
fout.close()

import os
os.path.exists('./oops.txt')

True

name = "oops.txt"
os.path.abspath('oops.txt')

'D:\Code\Python\code\oops.txt'

os.remove(name)

---------------------------------------------------------------------------

PermissionError                           Traceback (most recent call last)

<ipython-input-27-a353836641f9> in <module>()
----> 1 os.remove(name)


PermissionError: [WinError 32] 另一个程序正在使用此文件，进程无法访问。: 'oops.txt'

os.listdir('.')

['.ipynb_checkpoints',
 'introducting python.py',
 'Introduction.ipynb',
 'oops.txt']

os.getcwd()

'D:\Code\Python\code'

import calendar
calendar.isleap(2000)

True

from datetime import date
hallo = date(2014, 10, 31)
hallo.day

hallo.isoformat()

'2014-10-31'

now = date.today()
now

datetime.date(2018, 2, 7)

from datetime import timedelta
one = timedelta(days = 1)
tom = now + one * 6
tom

datetime.date(2018, 2, 6)

from datetime import time
noon = time(12, 0, 0)
noon.hour

from datetime import datetime
now = datetime.now()
now

datetime.datetime(2018, 1, 31, 15, 30, 45, 978714)

import time 
now = time.time()
now

1518007860.2188663

time.ctime(now)

'Wed Jan 31 15:34:00 2018'

time.localtime(now)

time.struct_time(tm_year=2018, tm_mon=1, tm_mday=31, tm_hour=15, tm_min=34, tm_sec=0, tm_wday=2, tm_yday=31, tm_isdst=0)

time.gmtime(now)

time.struct_time(tm_year=2018, tm_mon=1, tm_mday=31, tm_hour=7, tm_min=34, tm_sec=0, tm_wday=2, tm_yday=31, tm_isdst=0)

fmt = "It's %A, %B %d, %Y, local time %I:%M:%S:%p"
t = time.localtime()
t

time.struct_time(tm_year=2018, tm_mon=2, tm_mday=7, tm_hour=20, tm_min=51, tm_sec=5, tm_wday=2, tm_yday=38, tm_isdst=0)

time.strftime(fmt, t)

"It's Wednesday, January 31, 2018, local time 03:46:19:PM"

fmt = "%Y-%m-%d"
time.strptime("2014-04-28", fmt)

time.struct_time(tm_year=2014, tm_mon=4, tm_mday=28, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=0, tm_yday=118, tm_isdst=-1)