Python list derivation and generator expression usage example, python Generator
This article describes the Python list derivation and generator expression usage. We will share this with you for your reference. The details are as follows:
Like the list,List DerivationIt is also represented by square brackets [] and uses a abbreviated for loop. The first part is an
GeneratorGenerator function: The function body contains the yield keyword, the result of which the function executes is the generator, which is essentially an iterator.deffoo ():Print('First ------>') yield1Print('Second----->') yield2Print('Third----->') yield3Print('fouth----->') G=foo () fromCollectionsImportIteratorPrint(Isinstance (g,iterator))Print(g)Yield Features:1. Similar to return, can return a value, but the difference is that the
Additional example of listening file enddeftail (): F= Open ('file','R', encoding='Utf-8') F.seek (0,2) whileTrue:line=F.readline ()ifLine :yield LineImportTime Time.sleep (0.1) G=tail () forIinchg:Print(I.strip ())Send methodSend method:deffunc ():Print('*'*10) A=yield5Print(a)yield10g=func ()Print(g.__next__())Print(G.send ('Wenwen'))#print (g.__next__ ())From which yield begins to execute, send passes a value to the yieldSend cannot be used in the first touch generatorThe number of yield
Python masters road [9] python-based iterator and generator, python GeneratorIterator and Generator
1. iterator
An iterator is a way to access collection elements. The iterator object is accessed from the first element of the set until all elements are accessed. The iterator can only move forward without moving back, but there is nothing to do with it, because people seldom go back on the way of iteration.
10 free icon generator webpage designer, free enterprise icon Generator
In this presentation, we provide the best web designer 10 icon generator. These icon generators are free to use, and some are with advanced features that will help you generate compelling and attractive web pages for your website.
In order to pack them up, they can download them freely. Let's
MEAN framework learning notes, mean learning notesMEAN framework learning notes
There is very little information about the MEAN development framework. The main information is from the introduction on the learn. mean. io website. Therefore, with a zero-basic learning mentality, the
PHP Generator Simple instance, PHP generator
Generally when you iterate over a set of data, you need to create a data, assuming that the array is large, it consumes a lot of performance, or even causes memory shortage.Copy the Code code as follows:Fatal error:allowed memory size of 134217728 bytes exhausted (tried to allocate + bytes) in E:\php\test\index.php on L INE 5Range (1, 100000000);
PHP5.5 implemen
Random number, C language function is rand (), C + + is a random number generator (Random-number generator) = Distribution object (distribution object) + engine (engine);
To make a function generate a different random number each time, a static (static) local variable is required so that the distribution object and the engine can hold (hold) state, each time a new one is generated;
Generates a random inte
The Automatic Generator method is used in ionic2. The ionic2 generator method
Ionic generator is a command line function. ionic2 automatically helps us create applications, saving a lot of time and increasing our speed to develop a key part of a project.
Ionic generator allows us to automatically create the following p
List-generateda small topic: add 1 to the values in the list [0,1,2,3].Method 1:a=[0,1,2,3]b=[]for i in range(len(a)): b.append(i+1)a=bprint(a)Method 2:a = [1,3,4,6,7,7,8]for index,i in enumerate(a): a[index] +=1print(a)Method 3:a=[0,1,2,3,4]a=map(lambda x:x+1,a)print(a)for i in a: print(i)Method 4: (List-generated)a=[i+1 for i in range(10)]print(a)Did you see anything? Yes, the same functionality, the implementation of the code is becoming more and more streamlined.Get to the point: ge
List generator in Python, iterator understanding, python Generator
First, let's think about a problem. For example, if we want to generate a list between 0 and, what should we do?
Of course, it can be written
List1 = [1, 2, 3..., 100]
It can be seen that this method is not suitable for the growth of the list, so you can use the existing list in Python to generate a new list, called the list generative f
List-derivedy = [1,2,3,4,5,6,7,8= [1,4,9,16,25,36,49,64]# method One:x = [] for inch y: x. append (i*i)print(x)# method Two for inch y] Print (x) for in range (+)print for in y]print(x)Builder expressionExamplesy = [1,2,3,4,5,6,7,8]g= (i*i forIinchY#the list can be inferred, and the generator can also use an expressionPrint(g)Print(List (g))#use list to turn the generator into a list forIinchg:Print(
import si n while 1:yield n n = abs (sin (n)) *31# jump targets not state-sensitive, only to simplify Exampledef jump_to (val): If 0
There are a lot of places to study about generator-based state machines. The 1th is superficial to a large extent. We've arranged for stategen_test.py to use only functions, not classes (at least as I mean, the generator has a s
This example describes the Python builder generator usage. Share to everyone for your reference. Specifically as follows:
With yield, you can have a function generate a sequence of results, not just a value
For example:
?
1 2 3 4 5 6 7 8 9 10 11 12-13
def countdown (n): print "Counting Down" while N>0:yield n #生成一个n值 n-=1 >>> C = Countdown (5) >>> C.N EXT () Counting down 5 >>> c.next () 4 >>> c.next () 3
Next () calls th
Python3 generator and python3 Generator
1 ''' 2 list generation type 3''' 4 5 # a1 = [x for x in range (10)] 6 # a2 = [x * 2 for x in range (10)] 7 # print (a1) 8 # print (a2) 9 #10 # def fun1 (x ): 11 # return x ** 3 12 # a3 = [fun1 (x) for x in range (10)] 13 # print (a3) 14 #15 # list generation type 16 # Value Method 17 # B = ['asd ', 8, 9, 10] 18 # w, x, y, z = B 19 # print (w, x, y, z) 20 # print (B)
In order to learn how to use this software, I found that English is not good. All the documents are in English and cannot be understood, I thought about downloading a software. I thought it was all in English. I could not find a friend to learn with me, but I could not understand the English, so that I could remember it, it will be easy to use in the future. I 'd like to write more details. I used a version later than 7.0, and a friend sent me a version later than 6.5, so use 6.5, 7.0 I reported
Simple Example of Python2 random series generator and python2 series Generator
This article describes the Python2 random series generator. We will share this with you for your reference. The details are as follows:
# Filename: randNumber. pyimport randomwhile True: try: row = int (raw_input ('Enter the rows: ') cols = int (raw_input ('then Enter the cols :')) m
Python iterator and generator use instance, python generator instance
I. Iterators
The iterator is only a container object and implements the iterator protocol. It has two basic methods:
1) next MethodReturns the next element of the container.
2) _ iter _ MethodReturn iterator itself
The iterator can be created using the built-in iter method. See the example below:Copy codeThe Code is as follows:>>> I = ite
Measure the test taker's knowledge about the root-mean-square method and the root-mean-square method.Definition:
Root mean square method: the root mean square method is a statistical analysis method. It is used to extract the square sum of the dimensional tolerances in the dimension chain and then open the root to obta
Four arithmetic question generator (C ++) and four arithmetic question Generator
Question: Four arithmetic question generator.
Idea: Use the rand () % 100 function to generate a random positive integer of less than 100. Likewise, use the random function rand () % 4 to generate random 0, 1, 2 and 3 are random integers corresponding to the four conditions of additi
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.