Python special Syntax--filter, map, reduce, lambda

The  filter (function, sequence) executes function (item) on item in sequence, and the item that executes the result of true makes up a list/string/the Tuple (depending on the type of sequence) returns:deff (x):returnX% 2! = 0 andX% 3! =0PrintFilter (F, Range (2, 25)) #[5, 7, one, all, +, +]defF1 (x):returnX! ='a' PrintFilter (F1,"abcdef")#Bcdef Second, map (function, sequence) executes function (item) on item in sequence, and the result of execution consists of a list return:defcube (x):returnx*x*xPrintMap (cube, range (1, 11)) #[1, 8, 216, 343, 729 , +]defcube1 (x):returnX +xPrintMap (CUBE1,"ABCDE") #[' AA ', ' BB ', ' cc ', ' dd ', ' ee ']In addition, the map supports multiple sequence, which requires that the function also supports the corresponding number of parameter inputs:defAdd (x, y):returnx+yPrintMap (Add, Range (8), range (8)) #[0, 2, 4, 6, 8, ten, +]Status_ids= Map (LambdaX:x.get ('status__id'), snaps) three, reduce (function, sequence, starting_value) calls function for the item order in sequence, if there is starting_value can also be called as an initial value, for example, you can use to sum a list:defAdd (x, y):returnX +yPrintReduce (Add, range (1, 11)) Note:1+2+3+4+5+6+7+8+9+10reduce (Add, range (1, 11), 20) Note:1+2+3+4+5+6+7+8+9+10+20 iv.Lambda This is Python support an interesting syntax that allows you to quickly define a single line of the smallest function, similar to the C language of the macro, these functions, called Lambda, is borrowed from Lisp, can be used in any need function of the place: G=LambdaX:X * 2PrintG (3)#6Print(LambdaX:X * 2) (3)#6 Five, sortedAA= [   {'name':'Zhangsan',' Price': 20.01,'Date':'2015-01-09t01:00:00z'},   {'name':'Lisi',' Price': 10.01,'Date':'2013-01-09t01:00:00z'},   {'name':'Wangwu',' Price': 0.01,'Date':'2012-01-09t01:00:00z'}] Sorted (AA, Key=LambdaS:s.amount)#to sort a listSorted (AA, key=LambdaS:s.amount, reverse=True) AA= [<symbol:symbol object>, <symbol:symbol object>, <symbol:symbol object>] Sorted (AA, Key=Lambdas:s["Date"])#sort the symbol object, date is the symbol propertySorted (AA, key=Lambdas:s["Date"], reverse=True) Vi. for special usage  forIinchRange (4):    PrintIse=[x**2 forXinchRange (4)]PrintSe#[0, 1, 4, 9]SE=[x**2 forXinchRange (10)if  notx%2]PrintSe#[0, 4, approx.

Python special Syntax--filter, map, reduce, lambda