The third day of 2015-11-08

Calculator:

NUMX = "3 * 5/-2-(8*3/(20+3/2-5) + 4/(3-2) *-3)"

A collection of the following values [11,22,33,44,55,66,77,88,99,90 ...], saving all values greater than 66 to the first key in the dictionary, will be less than 66Value is saved to the value of the second key. That is: {'K1': Greater than 66,'K2': Less than 66}v1= [11,22,33,44,55,66,77,88,99,90]dicnum= {"K1":[],"K2":[]} forIinchv1:ifint (i) > 66: dicnum["K1"].append (i)Else: dicnum["K2"].append (i)Printdicnum["K1"]Printdicnum["K2"]PrintDicnum

v2 = [11,22,33,44,55,66,77,88,99,90]dicnum= {} forIinchV2:ifint (i) > 66:        if "K1" inchdicnum:dicnum["K1"].append (i)Else: dicnum["K1"] =[i]Else:        if "K2" inchdicnum:dicnum["K2"].append (i)Else: dicnum["K2"] =[i]Printdicnum["K1"]Printdicnum["K2"]

Collection

1. Default dictionary (sets the default format for dictionaries) Defaultdic
2. Ordered dictionary Orderdic
3. Counter counter
4. Queue-bidirectional queue

# default dictionary mydict = collections.defaultdict (list) mydict["K1"].append (1  )print mydict["K1"]

# ordered dictionary orderdict

An ordered dictionary maintains a list in a dictionary.

# Counter Counter  = [11,22,33,44,5544,3322,111= (11,22,33,44,222,5555,2222"  2343252632642362hfidsafhsifoesagoewagewaglsanldsa;lsf;sahflaf;saf;la"= collections. Counter (str1)print c2

Queue

1. Queue-one-way Queue FIFO Magazine

Import= queue.queue () q.put (2) q.put (3) q.put (23°c)print Q.get ()

Generator

Practice:<br> like the following tables:    [6, 13, 22, one] please follow the rules calculation:Compare the values of the large value on the right side, that is: [All, 6,] 0>22 and 6 Compare, put the big value on the right side, namely: [6, 22, one, one]and 99 compare, put the big value on the right side, namely: [Five, 6, one, one]99 and 42 Compare, put the big value in On the right, that is: [6,13, one, and 6 comparison, the big value on the right side, that is: [6, five, one, one, ...]

Li = [6, p, p, p] for in range (Len (LI)-1):    A in range ( M+1, Len (LI)):        if li[m]> li[n]:            = Li[n]            = Li[m]            = tempprint li

Function

Code blocks, broken down by function,

The difference between functional programming and process-oriented programming:

• Function: A function code is encapsulated in a function, it will not need to be repeated later, only the function can be called
• Object-oriented: classify and encapsulate functions to make development "faster, better and stronger ..."

The definition of a function has the following main points:

• def: A keyword that represents a function
• Function name: the names of functions, which are called later by function name
• Function Body: A series of logical calculations in a function, such as sending a message, calculating the maximum number in [11,22,38,888,2], etc...
• Parameters: Providing data for the function body
• Return value: Once the function has finished executing, it can return data to the caller.

• Built-in functions
• VARs () = = All variables of the current module

__DOC__ Note this document

__name__ the file name, as the current executable, content is __main__

__file__ file path

• All () returns false as long as it is empty
• Any () if one is true, returns True
• Reload () Reload reference file

• Custom functions

• def defines a keyword for a function
• Name of function
• function declaration
• function parameters

Formal parameters, parameter parameters, real parameter dynamic parameters

def func (*args):    print= [11,22,33,444,332,112]func (*li)

1. Accept multiple parameters
2. Internal Auto-structuring tuples
3. When called, add * to avoid automatically constructing tuples

Dynamic parameters to invoke the dictionary, you need to use * *

def func (* *args)    :print= {"echo" : 123,"rep": 234}func (**dic)

Default parameters

Do not use default values

• function return value

defEmail (ARG):PrintArgif __name__=="__main__": CPU= 100Ram= 50Disk= 500 forIinchRange (1):        ifCPU > 90: Alert="CPU Problems"Email (alert)ifDisk > 90: Alert="disk is having problems"Email (alert)ifRam > 80: Alert="Memory Problems"Email (alert)

• Import function

File operations

obj = open ("index.txt","R") Obj.seek (10 )#定位指针

Print Obj.tell () #输出指针位置

Print Obj.read () #输出内容

print Obj.tell ()

#输出指针位置

R Read

W Write

A append

&+

r+ Reading and writing

w+ Class W

A + Class A

The mode of opening the file is:

• R, read-only mode (default).
• W, write-only mode. "unreadable; not exist; create; delete content;"
• A, append mode. "Readable; not exist" create; "only append content;"

"+" means you can read and write a file at the same time

• r+, can read and write files. "readable; writable; can be added"
• w+, meaningless
• A +, with a

"U" means that the \ r \ n \ r \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ r or r+ mode can be converted automatically when reading

• RU
• R+u

"B" means processing binary files (e.g. FTP send upload ISO image file, Linux can be ignored, Windows process binary file should be labeled)

• Rb
• Wb
• Ab

2015-11-08 Third Day