python generator comprehension

in the method builder above def grep (Lines,searchtext):For the lines:if searchtext in Line:yield line;lines = grep (FileCount, ' Tom '); #查找带有tom substring for line in Lines:print (line);Output Result:' Tom ', 120,132Summarize:the role of the generator: when the program runs to yield, the running value is passed to the yield program and the output can be considered to be paused at this time when the program is in the suspended state when the __next

function of the result of the iterator2. Yield is similar to return, except that yield can return multiple values, and return can return only one value3, follow the value of the iterator obj.__next__ (), trigger function execution, when run once obj.__next__ () The function will stop to the first yield, that is to say you write a few obj.__next__ () you function stop in the number of yieldExample:deffoo (x):Print('Play') whileX>0:yieldx x-=1Print('Game over') G=foo (5)Print(g.__next__())Pri

#define a generator that is the same as a function, except that the yield keyword, which is actually similar to returndefEasyyield ():yield1yield2#instantiate the generator with an object, bind to the variable, and get the content of yield by nextA =Easyyield ()Print(Next (a))Print(Next (a))#the second instance, the upgraded version of the generatordefLibs (): A, B=0,1 whiletrue:a,b= b,a+byielda foreachinch

This article describes how to use Python iterators and generators. This article describes the next method, the _ iter _ method and examples of the iterator, and the code examples of the generator, for more information, see 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 _

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1. Essence: Iterator2. Generator function:def func (): A=1 b=2 Yield a #返回第一个值 Yield b #返回第二个值ret = func () #拿到一个生成器Print (Next (ret)) #取第一个值Print (Next (ret)) #取第二个值Print (ret) #取第三个值 An error because there is no third value3. example of the generator listener file inputImport timedef tail (filename): with open (filename) as F: F.seek (0, 2) #从文件末尾算起 While True:

Recently, the school has been a fan of my automation department of the bitter children's shoes left to do lesson set, almost bored to explode--with VB to implement the function generator, (language not limited)Guys don't know where to get the MATLAB version, so dozens of people on the basis of the revision modified to muddle through, but I really do not want to use MATLABWrite (if caught, dozens of people 0 points, that scene. ), with VB? Learn a lang

Python Verification code 6-bit Auto generator！ /usr/bin/env python#-*-coding:utf-8-*- ImportRandom tem="" forIinchRange (6): Digi= Random.randrange (0,11) ifDigi = = 1orDigi = = 5:## # # #当randrange (0,11) randomly generated number is 1 or 5 when,,,,:) is not a bit around Ah, hahahanum = Random.randrange (1,10) Num=str (num) TEM+=NumElse: ZM= Ra

One or three meta-expressionsTernary expressions, also known as If,else's compact form. The specific usage is as follows:def Max (A, b ): if a>B: return a else: return b def Max (A, b ): return if Else b The functions implemented by the above two functions are exactly the same. A If a>b else B in the second function is a ternary expression. The left is the value returned when the condition is true, the middle is the judging condition, and the right is the value of the co

Iterations, that is, repeating things many times, Python allows you to iterate over sequences, dictionaries, and other objects with a for loop. When other objects are iterated, you need to implement the __iter__ method in other objects. The __iter__ method returns an iterator, which is the object with the next method. When the next method is called, the iterator returns its next value. If the next method is invoked, but the iterator has no value to re

Python Password generator,,,,,,,,,,,,,,,,, From random import randrange, sample# definition list password_list = [' Z ', ' y ', ' x ', ' w ', ' V ', ' u ', ' t ', ' s ', ' r ', ' Q ', ' P ', ' O ', ' n ', ' m ', ' l ', ' K ', ' j ', ' I ', ' h ', ' G ', ' f ', ' e ', ' d ', ' C ', ' B ', ' A ', ' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ', ' 7 ', ' 8 ', ' 9 ', '! ', ' @ ', ' # ', ' $ ', '% ', ' ^ ', ' '

(): #定义函数 passclass Foo: #定义类 Pass2. Classification of namespaces Built-in namespaces: As the Python interpreter starts, it includes exception types, built-in functions, and special methods, which can be called anywhere in the code Print (sum) print (max) print (min) print (max ([builtinsfor]) import i in Dir (builtins): #打印所有的内置函数 print (i) Copy code result: C: \python\python36\python.

Python iterator and Generator I. iteratorsThe 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:>>> I = ITER ('abc ')>>> I. Next ()'A'>>> I. Next ()'B'>>> I. Next ()'C'>>> I. Nex

1. List deduction 1234567891011 numbers = [i for i in range(10) if i % 2 == 0]print(numbers)seq = ["one", "two", "three"]for i, element in enumerate(seq):print(i, element)def treatment(pos, element):return (‘%d: %s‘ % (pos, element))print ([treatment(i, element) for i, element in enumerate(seq)]) 123456 enumerate(sequence, [start=0])Return an enumerate object. sequence must be a sequence, an iterator, or some other object which supports iteration. The n

Tag: Gen log file one requires Std to get Python astA function that contains yield, which is executed to obtain a code flow that requires next to push execution.Code flow is like toothpaste, next is like squeezing toothpaste.def Odd (): Print ('Step 1') yield 1 print('step 2') yield (3) print('step 3') Yield(5)When you call the generator, you first generate a

This article is mainly for you in detail how Python uses the generator to achieve the iterative object, has a certain reference value, interested in small partners can refer to, hope to help everyone. Case Analysis: A class of an iterative object that iterates over all the primes in a given range: PN = Number (1, 30) For k in PN: Print (k) The result is: 2,3,5,7,11,13,17,19,23,29 How to solve this p

This article describes how to implement a random password dictionary generator in python. if you need a dictionary generator, you can refer to all the passwords you want to use. the algorithm is either nested too deep, or memory consumption (will overflow ). later, I selected an algorithm with a low probability of simple repetition. the code is as follows:

'% (stop-start)) returnResreturnInner@timmer#Index=timmer (Index)defindex (): Time.sleep (1) Print('Welecome to index') return1111Res=index ()Print(RES)2. iteratorsIterators : iterators are tools that iterate.What is an iteration? : Refers to a repeating process, each repetition is called an iteration, and the result of each repetition is the initial value of the next repetitionWhy do we have iterators? : For sequence type: Str,list,tuple, you can rely on the index to iterate over the valu

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This example describes the Python builder generator usage. Share to everyone for your reference. Specific as follows: With yield, you can let a function generate a result sequence, not just a value For example: def countdown (n): print "Counting" while n>0: yield n #生成一个n值 Next () calls the generator function to run until the next yield statement,