aws lambda python 3

Python function Summary-decorator and lambdaThis article is still a learning note. The structure of this article first talks about the decorator and then lambda expressions. The decorator has many contents. First, the decorator syntax is briefly introduced, and then the details that should be noted when understanding and using the decorator without parameters are described in detail, then a simple cache dec

):The call function is iterated over the item order in sequence and, if there is a starting_value, it can be invoked as an initial value, for example, to sum the list: >>> def Add (x,y): return x + y >>> reduce (add, range (1, one)) 55 (note: 1+2+3+4+5+6+7+8+9+10) gt;>> reduce (Add, range (1, a) 75 (note: 1+2+3+4+5+6+7+8+9+10+20) 4.lambda:This is a very interesting syntax that

1.yield meaning of production and generation, the function with yield in Python is called the Generator (Generator)The larger the #生成10000个元素的List value of the ' for I in range ', the larger the memory consumed in the run will be 10000 for J in Xrange (10000) #xrange返回的不是List, but a Iterable object Each iteration returns the next value, taking up a very small amount of memory space "Def Readfilebyyield (XPath): With open (XPath, ' RB ') as Ty: For

One of the interview questions.Does the following code work?L = [1,2,3,4,5]for i in Range (0,len (l)): print I if l[i]% 2 = = 0: del l[i]print lResults:Traceback (most recent): File "D:\1.py", line 3, Ah, because with the execution of the DEL () statement, the list has fewer elements, but for has been set [0,5]:i = 0,l[i] = 1 not even skippedi = 1,l[i] = 2 is even, L = [1,3,4,5]i = 2,l[i] = 4 is even, l=[1,3,5]i =

Lambdaanonymous function, the core is as an operator, processing logic only one row but with functions of the characteristics, the core for functional programmingTernary operatorsEssentially a simplified version of the if branch that satisfies the value returned by the IF condition before the condition returns the value after else# 　　MapThe mapping function, which sequentially passes the values in the Iterated object (which can be multiple) to the function, and then returns the generator (length

Recently in the analysis of the data, with some simple filtering, but also learned, lambda and startwith some usage, write a memo below, first understand lambda. This is a small usage of a similar function, which can be used in conjunction with the filter:>>> Xiaoluo = lambda x,y:x+y>>> print Xiaoluo ($) 3>>> print Xia

(function, sequence, starting_value)The function is called on an iteration of the item order in sequence, and if there is starting_value, it can also be called as an initial value, for example to sum the list:>>> def add(x, y): returnX + y>>>Reduce (Add, range (1, One)) -Note1+2+3+4+5+6+7+8+9+Ten）>>>Reduce (Add, range (1, One), -) theNote1+2+3+4+5+6+7+8+9+Ten+ -）[4] LambdaThis is a fun syntax for

right, to reduce the sequence to a single subsequence example, (λx,y:x+y,[1,2,3,4,5]) (1+2)) (+3) +4). If it is initially present, it is placed before the calculated sequence item and is left as the default value when the sequence is empty.1 def Addnum (num1,num2): 2 return num1+num234 list2={1,2,3,4,5,6}5Print Reduce (Addnum, List2)Code interpretation: Calculate the value of 1+2 first, then pass the computed value as the first parameter into Add

(1) Lambda A lambda is a python that creates an anonymous function in the form of the following syntax: Lambda [arg1[, arg2, ... argn]]: expressionUse examples: #使用法一 fun = lambda x,y:x+y print Fun (1,2) #输出结果为: 3 #使用法二 print (

(1, 100))Print reduce (ADD1, range (1, 100), 20)# 4950 (Note: 1+2+...+99)# 4970 (Note: 1+2+...+99+20)The function is called on an iteration of the item order in sequence, and if there is starting_value, it can also be called as an initial value, for example to sum the list:4 Lambda:g = lambda s:s + ". FSH"Print g ("haha")Print (Lambda x:x * 2) (3)# # HAHA.FSH# 6

expressions, which is more convenientAs you can see from the above, lambda expressions can be conveniently used instead of simple functions.Two or three-dollar operation1, see what is ternary operation2, Python's ternary operation format is as follows:result= value 1 if x1>>>deff (x, y):2 returnX-yifX>yElseABS (xy)3 #if x is greater than Y, it returns an X-y value, otherwise it returns the absolute val

Yield (saves the execution state of the function)A function with yield is a generator, which, unlike a normal function, generates a generator that looks like a function call, but does not execute any function code until it calls next () (which is automatically called next () in the For loop) to begin execution. Although the execution process still executes according to the process of the function, each execution to a yield statement is interrupted and an iteration value is returned, and the next

Map function: Prototype: Map (function, sequence), which maps a list to another list,How to use:def f (x):Return x**2L = Range (1,10)Map (f,l)OUT[3]: [1, 4, 9, 16, 25, 36, 49, 64, 81] Reduce function Prototype: reduce (function, sequence, startvalue), which is to summarize a list as an output,How to use:def f2 (x, y):Return X+yReduce (f1,l)OUT[7]: 45Reduce (f2,l,10)OUT[8]: 55 Filter function Prototype: filter (function

意结构')Print(Sumtree (L))##间接函数调用defEcho (message):Print(message)defIndirect (Func,args): func (args) indirect (echo,'Shixingwen') Schedule1=[(Echo,'spam! '), (Echo,'ham!') ] for(Func,args)inchSchedule1:func (args)Print('# #间接调用函数')Print(Echo.__name__)## #python function AnnotationsdefFunc (A:'spam', B: (1,3), c:float):returnA + B +CPrint('# #函数注释')Print(Func-)) Zhushi= Func.__annotations__ Print(Zhushi,'\ n') forArgsinchZhushi:Print(Args,'=', Zhushi

One, lambda expression 1 >>> def add (x, y): #定义一个加法函数 2 return x+y #返回两个参数的相加的值 3 4 >>> z=f (3, 4) 5 >>> print (z) 6 7 #调用加法函数返回7 7 >>> Lambda x,y:x+ Y 8 As you can see from the above, lambda expressions can be conveniently used instead of simple functions.Two or three-doll

Lambda expression, this bird thing is to define a function in one line of statements. Http://woodpecker.org.cn/diveintopython/power_of_introspection/lambda_functions.html >>> def f (x): ... Return x*2 ... >>> F (3) 6 >>> g = lambda x:x*2 >>> g (3) 6 >>> (lambda x

Map function: Prototype: Map (function, sequence), which maps a list to another list, How to use: def f (x): Return x**2 L = Range (1,10) Map (f,l) OUT[3]: [1, 4, 9, 16, 25, 36, 49, 64, 81] Reduce function Prototype: reduce (function, sequence, startvalue), which is to summarize a list as an output,How to use: def f2 (x, y): Return X+y Reduce (f1,l) OUT[7]: 45 Reduce (f2,l,10) OUT[8]: 55 Filter function Prototype:

One of the most important aspects of Python is functional programming (functional programming), where you can transfer functions where parameters and values are transferred.Lambda x:x%3 = = 0and the following equivalence:def by_three (x): return x%3 = = 0We don't need to really give the function a name, it can also work and get the result. This is why the func

be processed,initval is the initial value 2. Code1 array=[1,2,3,4,5,6,7]2Lambda x,y:x+y3 ans2= reduce (add , array,0)4print ans3. Function prototypes1 defreduce (function,array,initval):2TMP =list (array)3 ifInitval isNone:4Ans = list.pop (0)#take the first element of the list and delete5 Else:6Ans =Initval7 foreachinchtmp:8Ans =function (Ans,each)9 returnans;Ten Oneans2= Reduce (add,array,0)5. Apply1. Basic formAPPLY(FUnCtion