June+24th+2016+by+David+Ye

1."==", "=" & ">=" == 意为判断前后是否相等，如下例所示： code format="python" >>> 10 == 8 False code = 意为赋值，如：

code format="python" >>> a = 10 >>> print(a) 10 code >= 大于等于号，如： code format="python" age = 20 >>> Old_enough = age >= 17 >>> Old_enough True code 2.Logical Operators (武老大高一的时候讲过，不会的要被查水表了) (1) And: 只有在input都为"True"的条件下output才为"True" (2) Or: 只要input中有一个为"True"那么output就为"True" (3)Not: "False"变"True","True"变"False"

3.Truth Tables
 * ~ a ||~ b ||~ a or b ||
 * F || F || F ||
 * F || T || T ||
 * T || F || T ||
 * T || T || T ||


 * ~ a ||~ b ||~ a and b ||
 * False || False || False ||
 * False || True || False ||
 * True || False || False ||
 * True || True || True ||

4. Break The **break** statement is used to immediately leave the body of its loop. The next statement to be executed is the first one after the body: code format="python" for i in [12, 16, 17, 24, 29]: if i % 2 == 1: break print(i) print(done) code 5.Continue This is a control flow statement that causes the program to immediately skip the processing of the rest of the body of the loop, //for the current iteration//. But the loop still carries on running for its remaining iterations: code format="python" for i in [12, 16, 17, 24, 29, 30]: if i % 2 == 1: continue print(i) print("done")
 * ~ a ||~ not a ||
 * F || T ||
 * T || F ||

code 6.Return 跳出函数，把后面作为返回值，只能用于函数中.

7.Comments and Notations are very important! (To remind yourself)

8.Composition 即函数调用函数，在之前用五个五角星组一个大五角星一题中大家已经练习过了.

9.Recursion 即函数调用自己，递归，如： code format="python" def Factorial(n): if n == 0 or n == 1: return 1 else: return(n * Factorial(n - 1))

print(Factorial(6)) code

Finally, the homework is to write a program to represent the steps of the Hanoi Tower. -different sides of disks on the first rod -there are three rods in total -only one disk can be moved at a time -each move consists of taking the upper disk from one of thstacks and placing it on top of another stack -no disk may be placed on top of a smaller disk

Hanoi(a, c, n) Hanoi(a, c, 1) Hanoi(a, c, n-1) Leave the calculations to your computer show each of the steps!