Python Learning Day5

1. String formatting
Percent semicolon formatting
s = "I am%s"% ' Wyx ' #通过位置传递参数, formatted string type

s = ' I am% (name) s '% {' name ': ' Wyx '} #通过命名传递参数

s = ' I have percent%.2f '% 1.111 #小数点类型

s = ' I have percent% (p). 2f '% {' P ': 1.1} #小数点命名传递参数

Format formats
#索引传参
S1 = ' I am {0} age {1} age{1} '. Format (' Wyx ', 123)

#名字传参, and format: s for string formatting:d representing numeric formatting
S2 = ' I am {name:s} age{age:d} '. Format (name= ' Wyx ', age=18)

#位置传递参数, {} indicates that any parameter can be accepted.
S3 = ' I am {} age {} {} '. Format (' Wyx ', ' haha ')

# *[] Pass each parameter in the list to the location via a list
S4 = ' I am {} age {} {} '. Format (*[' Wyx ', ' haha ')

# **{} passes value to the corresponding key value: s represents character formatting:d number formatting
S5 = ' I am {name:s} age {Age:d} really {name:s} '. Format (**{"name": ' Wyx ', ' Age ': 18})

#: 2f stands for two digits after the decimal point
S6 = ' I have {percent:.2f} '. Format (percent=1.13233244)

#通过元素索引来传递参数
S7 = ' I am {0[0]} Age{0[0]} '. Format ([' Wyx ', ' cxl ', [18,19]])

#:b binary: o octal:d integers: x 16 binary:% converted to percent
S8 = ' numbes:{:b}{:o}{:d}{:x}{%} '. Format (15,15,15,15,15w)

Generator
def func ():
Print (111)
Yield 1
Print (2222)
Yield 2
Print (333)
Yield 3

ret = func ()
R1 = ret.__next__ () #进入函数找到yield, gets the data after yield 1 #相当于return yield after the data 1
Print (R1)
r2 = ret.__next__ ()
Print (R2)
R3 = ret.__next__ ()
Print (R3)

Def myrange (ARG): #自己写的range函数
Start = 0
While True:
If Start>arg:
Return
Yield start
Start+=1
ret = myrange (10)
R=ret.__next__ ()
Print (R)

Iterators

def func (N):
N+=1
If n>5:
Return ' End '
return func (N)
ret = func (1)
Print (ret)

Module
Existence mode:
Files folder

Using modules:
Use after import first

Modules: Built-in modules third-party module custom modules

The basis for importing modules:
Import Sys
Sys.path

Import Module Mode:
Import ModuleName
From xx import xx as oo

Module naming rules: cannot be the same as the built-in module name

Module installation
SOURCE installation: Download the source code via python.x setup.py Install
PIP Installation: PIP3 install ModuleName

1. Serialization related

Import JSON
Import Pickle

DIC = {' A ': ' B '}
#json. Dumps (DIC) serialization: Converting a Python base type to a string

DiC = ' {' A ': ' B '} '
#json. Loads (DIC) deserialization: Converting a string to a Python base type

Import Pickle
Li = [11,22,33]
r = Pickle.dumps (LI)
Print (R)

result = Pickle.loads (r)
Print (Result)

Json/pickle
JSON is more suitable for cross-language/pickle only for Python
+-------------------+---------------+
| Python | JSON |
+===================+===============+
| Dict | Object |
+-------------------+---------------+
| List, tuple | Array |
+-------------------+---------------+
| str | string |
+-------------------+---------------+
| int, float | number |
+-------------------+---------------+
| True | true |
+-------------------+---------------+
| False | False |
+-------------------+---------------+
| None | null |

Time Module
Time&datetime

Python Learning Day5