Python Learning Five "program control structure-Select structure && loop Structure"

Directly talk about multi-branch structure (Chained), it is relatively simple, just summarize:

Like what

Example 1: Converting an exam score to a grade
Score >= 90
A
Score >= 80
B
Score >= 70
C
Score >= 60
D
Score < 60
E

Python Statement implementations:

Score =98if score>=90:    print ' A ' elif score>=80:    print ' B ' elif score>=70:    print ' C ' elif score>= :    print ' D ' else:     print ' E ' </span>

Output A

Example 2: Finding the solution of a one-dimensional two-time equation

Python Code implementation:

Import matha=float (raw_input (' Input A: ')) B=float (raw_input (' Input B: ')) C=float (raw_input (' Input C: ')) if a==0:    print ' not quadratic ' else:    delta=b**2-4*a*c    if delta <0:        print ' no real root! '    Elif Delta ==0:        print ' Only one root is ',-b/(2*a)    else:        root =math.sqrt (delta)        s1= (-b+root)/(2*a)        s2= (-b-root)/(2*a)    print ' Both distinct solutions is: ', s1,s2

The results of the operation are as follows:

Example 3: Calculating the value of a 1+2+3+...+10
Note: The range function generates 0, 1, ..., 10 sequences

Code implementation:

s = 0i=1for I in range (one):    s + = i      print ' sum is ', s

Output

Example 4: Calculating the constant E

Idea: (1) Call function, (2) write function yourself

Code implementation

Import mathe = 1for i in range (1,100):   e + = 1.0/math.factorial (i) print ' E is ', E

Output: E is 2.71828182846

E = 1fib=1for i in range (1, +):    fib *= i    e +=1.0/fibprint ' E is ', E

Output: E is 2.71828182846

You can see that the two methods are the same, but note the second, the second or more lines below the For loop, to keep the left alignment with the first row, otherwise run as a single statement

Attention:

Range (2, 10) = [2, 3, 4, 5, 6, 7, 8, 9]
Range (2, 10, 3) = [2, 5, 8]
Range (10, 2,-1) =[10, 9, 8, 7, 6, 5, 4, 3]

Python Learning Five "program control structure-Select structure && loop Structure"