Python

Scenario: When a colleague needs you to pass a file on the server to him, you can actually use Python to open a downloader, directly to the URL to a colleague.1) View the Python version (because there are some differences between the Python2 and

common methods for locating individual elements Take the Baidu search box Preexcitation as an example, the blue position is the property that navigates to the input box:

String Common operations JudgeVariable. EndsWith ("trailing character"): determines the ending string.Variable. Isalnum (): Determines whether it is a letter or a number.Variable. Isalpha (): Determines whether it is an English

1. BackgroundZephyr Project Flash and RAM space is tight, with very strong optimization requirements.The premise of optimization is to quantify the target, then how to quantify the amount of flash and RAM usage?After quantification, the

# polymorphism: One interface, multiple implementations Class Animal: def __init__ (self,name): Self.name=name Def talk (self): Print ("Animal can Talk") # Xia Chu obj represents passing in different objects, invoking the same interface

On-the-ground Python "16th chapter": The Web Front-end foundation of jquery One, what is jquery?jquery is a library of JavaScript functions.jquery is a lightweight "write less, do more" JavaScript library.The jquery library contains the following

Python output file contents to network port$ cat mysockettest.pyImport SysImport timeImport socketif __name__ = = "__main__":If Len (SYS.ARGV) Print >> sys.stderr, "Usage:mySocketTest.py "Exit (-1)Host = Sys.argv[1]Port = Int

What is an exception? Errors detected during program operation are called exceptions.We can catch and handle these exceptions through the program, which involves the try and raise statementsFirst look at the Try statement:Execution mode:

Enumerate (iterable,start=0)(the subscript start position of the custom list) list variables, to define the number of open: default is 0 start#!/usr/bin/env python#-*-coding:utf-8-*-a=["Juvenile","Youth","Adult","old age"] forKvinchEnumerate (a,1):

Shopping CartFunctional Requirements:Require users to enter total assets, for example: 5000Display the list of items, let the user select the item according to the serial number, add the shopping cartPurchase, if the total amount of goods is greater

How to copy a list:　　lst = [1,2,3] lst1 = lst[:] # one way lst2 = list(lst) # another The correct way to delete data:Num_list = [1, 2, 3, 4, 5] Print (num_list) for item in num_list[:]: If Item = = 2:num_list.remove (item) Else:

#1#Here is a list of edges:T = [('Bob','Eve'),('Alice','Carol'),('Eve','Frank'),('Alice','Doug'),('Frank','Ginger'), ('Eve','Howard'),('Carol','Irene'),('Frank','Jeff'),('Doug','Kathy'),('Bob','Luis'), ('Alice','Bob'),('Bob','Mabel'

1. Dictionary Dict1.1Dictionary Definitions>>> d={' Adam ': Up, ' Lisa ': $, ' Bart ': 59}1.2Dictionary Access1.2.1key Method AccessDict[key]>>> d[' Adam ']95Determine if key is--in in Dict(can only Judge key)>>> D{' Lisa ': $, ' Adam ': Up, ' Bart '

1. Magic Method-Definitiondefined in a class (such as __len__ in __str__,list in object), do not need to call the method directly,some functions or operators in Python call the corresponding special method (such as print call __str__,len () call

Import GeventDef f1 (): Print ("Print in F1") Gevent.sleep (2) Print ("Switch to Foo again")def f2 (): Print ("Print in F2") Gevent.sleep (1) Print ("Switch to F2 again")Def f3 (): Print ("Print in F3") Gevent.sleep (0)

1. Read the contents of the fileImport CodecsF=codecs.open (' 1.txt ', ' RB ')Print (F.read ())F.close ()2. Write a new fileImport CodecsF=codecs.open (' 2.txt ', ' WB ')F.write (' Hello World ')F.close ()Special usage of 3.WithImport CodecsWith

Chicken soup:Ideal, you are like a flower in the severe winter not blooming plum blossom, your life in the sky of the snow is so small, so fragile. As if a gust of north wind blows, can blow you to the best. Will you wither if you never bloom? Never

One or three-tuple operator# when the condition is met 1 o'clock, the res= value is 1; otherwise res= value 2 if Else value 2To illustrate:res=10# Simple If Else statement if abs (res) >0: = 10**2else: Res =0# implemented with ternary

1, through the language features to achieve:For I in Range (0,100): When True: try: # do stuff except somespecificexception: continue Break　2, through the third-party library implementation:Pip Install

Collection.namedtuple is a factory function that can be used to construct a tuple with a field name and a class with a name-the class with the name is very helpful to the debugger. And an instance of a class built with namedtuple consumes the same