Python Learning notes (15) Loop design

Original chain: http://www.cnblogs.com/vamei/archive/2012/07/09/2582435.html

Note: Zip () is inconsistent in Python2 3

#15th talk cycle design#loops in front are learning, simple loops forIinchRange (10):    Print(i**2)#It's a very simple loop.#Range ()s='Abcdefghijk' forIinchRange (0, Len (s), 2):#starting with subscript 0, the number of elements returned by the Len () function, and step Step 2    Print(S[i])#output Result: A C e g i k#Step step This concept is a concept that was introduced before learning the subscript in the list#Range function to define the step size of each cycle of the upper and lower bounds, respectively#the list is separated by:#Note that the number produced by range is not capped. forIinchRange (0, 5, 2):    Print(i)#Output: 0,2,4#Enumerate () for(Index, Char)inchEnumerate (s):Print(index, char)" "Output Result: 0 A1 B2 C3 d4 e5 f6 G7 h8 I9 J10 k" "#In the output, the enumerate () function returns a tuple, and then two elements are assigned to the index char#Print the subscript and the elements. Char characters C language more#zip ()m1 = [1, 2, 3]m2= [9, 8, 7]m3= ['a','b','C'] for(A,B,C)inchZip (m1,m2,m3):Print((a,b,c))#Output Result: (1, 9, ' a ')#(2, 8, ' B ')#(3, 7, ' C ')#The zip () function, which is to remove an element from multiple lists, sequentially, merges the elements from the different list into a tuple and returns#function of the zip () function, aggregate list#For the next 3 variables, must be the list inside enough, list inside there are 4 can also, m1= [1,2,3,4]#The output is constant, but for the subsequent change of 4 variables, an error will be#Valueerror:not enough values to unpack (expected 4, got 3)#get only 3 variables, expected to be 4 variablesM1= [A]m2= [9,8,7]zipped= Zip (m1,m2)#zip () extracts an element from the list M1 m2, forming a tuple and assigning it to zippedPrint(*zipped)#Output: (1, 9) (2, 8) (3, 7)list (Zip (m1,m2))#output list:[(1, 9), (2, 8), (3, 7)]#This is the aggregation#exploded list#the ZIP function is inconsistent in Python2 3 .#Python2 Implementation

Then continue to python3 the zip ()

#Python3x= (A) y= (4,5,6) Z= (7,8,9) n=list (Zip (x, y, z))Print(n)#[(1, 4, 7), (2, 5, 8), (3, 6, 9)]m= List (Zip (*N))Print(m)#[(1, 2, 3), (4, 5, 6), (7, 8, 9)]#are implemented by list.#according to official documentsx = (A) y= (4,5,6) zipped=zip (x, y) List (zipped)#[(1, 4), (2, 5), (3, 6)]#Note: Try it yourselfPrint(zipped)<zip Object at 0x0000023a74ed6748>Print(List (zipped)) [(1, 4), (2, 5), (3, 6)]#Continue documentx2, y2 = Zip (*zip (x, y))#here the zip (x, y) cannot be used zipped, although we have previously assigned a value, Python will think that there is not enough value to solveX2#(1, 2, 3)y2#(4, 5, 6)

Python Learning notes (15) Loop design