python(三)

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一些常用的函数

函数原型:range(start, end, scan):

函数含义:[strat,start+scan,start+2*scan,start+3*scan……,end]

参数含义:start:计数从start开始。默认是从0开始。例如range(5)等价于range(0, 5);

              end:技术到end结束,但不包括end.例如:range(0, 5) 是[0, 1, 2, 3, 4]没有5

              scan:每次跳跃的间距,默认为1。例如:range(0, 5) 等价于 range(0, 5, 1) ;range(5,0,-1) ,内容是 [5,4,3,2,1]。

函数原型: number1(整数数值)<<number2(整数数值)

函数含义:number1*pow(2,number2)


对异常的处理:

try:    <body>except <ErrorType1>:    <handler1>except <ErrorType2>:    <handler2>except <ErrorType3>:    <handler3>except:    <handler0>else:    <process_else>finall:    <process_finally>


例如:
while True:try:x = int(input("Please enter a number: "))breakexcept ValueError:print("Oops! That was no valid . Try again...")

运行:

例如:

while True:try:x = int(input("Please enter a number: "))breakexcept ValueError:print("Oops! That was no valid . Try again...")else:print("procell_else")finally:print("procell_finally")

运行:

完成代码示例:

def main():try:number1,number2 = eval(input("Enter two numbers, separated by a comma:"))                result = number1 / number2except ZeroDivisionError:print("Division by zero!")except SyntaxError:print("A comma may be missing in the input")except:print("Something wrong in rhe input")else:print("No exceptions, the result is", result)finally:print("executing the final clause")main() 


布尔操作符: 优先级(not  > and > or)

tutrle库常用的函数:

forward(distance)将箭头移到某一指定坐标left(angle) right(angle)penup()提起笔,用于另起一个地方绘制时使用,与pendown()配对使用goto(x,y)home()circle(radius)speed()