Python functions Advanced Features

slices(intercept element, can operate list,tuple,string)

L = List (range)  #  [0,1,2,3,...,]l[0:10] = l[:10]  #  intercept the first 10 numbers [0,1,2,..., 9 ]# l[-10:  #  10 numbers after intercept    [90,91,92,...,]l[10:20]  #  intercept elements of 10-20 positions [ 10,11,12,13,...,]l[:10:2]  #  first 10 numbers, every two take one [0,2,4,6,8]L[::5]  # all numbers, fetch 1 per 5 [0,5,10,...,] l[:]  #  Copy the original array

iterative for...in ...

• Iterative Dict

D = {'a'b'c': 3}  #  By default, the Dict iteration is key. If you want to iterate over value, you can use for value in D.values (), if you want to iterate both key and value at the same time, you can use for K and V in D.items ()

• Iteration List

 for  in Enumerate (["a""b""C"  ]):    Print(i, value)  #  Iteration list needs to use the Enumerate function #  0 A#  1 b#  2 C

List-generated

List (range (1,11))#generate [,..,][X*x forXinchRange (1,11)]#build [1*1,2*2,3*3,..., 10*10]#list Generation and if-judging[X*x forXinchRange (1,11)ifx%2 ==0]#build [2*2,4*4,6*6,8*8,10*10]#double-layer loop generation full array[X+y forXinch "ABC"  forYinch "XYZ"]#generate [' AX ', ' AY ', ' AZ ', ' BX ', ' by ', ' BZ ', ' CX ', ' CY ', ' CZ ']

Generator: Genterator (side loop calculation, if a function contains the yield keyword, then the function is a generator)

• The list generation [] should be ()

 for  in range (1,10)#  Call Method:# each time you call the next () method to get the element, you can only get one for   theNext () method    print(n) is constantly called inside the For loop

• Using the yield keyword

def fib (max):     = 0, 0, 1 while     n < Max:        yield  b        = b, A + b        = n + 1
   return'done'

iterators

• An object that can act directly on a for loop iterable

 from Import iterableisinstance ([], iterable)   # True use Isinstance () to determine whether the Iterable object

• An object that can be called by next () and continually returns the next value Iterator

 from Import   for in range (Iterator)    # use Isinstance () to determine if the object is Iterator, The iterator object is an inert evaluation and is evaluated only when needed

Python functions Advanced Features