1.定义一个函数quadratic(a, b, c)，接收3个参数，返回一元二次方程：ax2 + bx + c = 0的两个解
# -*- coding: utf-8 -*-
import math
def quadratic(a, b, c):
if not isinstance(a,(int,float)):
raise TypeError("bad operand type")
if b==0&a==0:
return "参数a,b不能同时为0"
if b*b-4*a*c<0:
return "该方程无解"
elif b*b-4*a*c==0:
if a==0:
x=-(b/c)
return x
elif a!=0:
x=-b/(2*a)
return x
elif b*b-4*a*c>0:
x=(-b+math.sqrt(b*b-4*a*c))/(2*a)
y=(-b-math.sqrt(b*b-4*a*c))/(2*a)
return x,y
# 测试:
print("quadratic(2, 3, 1) =", quadratic(2, 3, 1))
print("quadratic(1, 3, -4) =", quadratic(1, 3, -4))
if quadratic(2, 3, 1) != (-0.5, -1.0):
print("测试失败")
elif quadratic(1, 3, -4) != (1.0, -4.0):
print("测试失败")
else:
print("测试成功")
2.去除字符串首尾的空格
# -*- coding: utf-8 -*-
def trim(s):
while s[:1] == " ":
s = s[1:]
while s[-1:] == " ":
s = s[:-1]
return s
if trim("hello ") != "hello":
print("失败")
else:
print("成功")
<2>
# -*- coding: utf-8 -*-
def trim(s):
while len(s) > 0 and s[0] == " ":
s = s[1:]
while len(s) > 0 and s[-1] == " ":
s = s[:-1]
return s
if trim("hello ") != "hello":
print("失败")
else:
print("成功")