python learning1.py

# 廖雪峰的官方网站 python教材 1~4章

# 格式控制符语法

print('Hello, %s' % 'world')
print('hello, %s, you have %d dollars' % ('mickael', 1000))
print('hello, {0:s}, your grade {1:.1f}%'.format('xiaoming', 17.125))

s1 = 72
s2 = 85
improve = (s2-s1)/s1 * 100
print('hello, {0:s}, your grade improved by {1:.1f}%'.format("xiaoming", improve));

# 列表 list

classmate = ['xiaoming','xiaozhao','xiaohong']
print(classmate)

print(len(classmate))

print(classmate[1])

classmate.insert(1,"Jack")
print(classmate)

classmate.pop()
print(classmate)

classmate.pop(1)
print(classmate)

classmate[1] = "Sarah"
print(classmate)

L = ['apple', 123, True]
print(L)

# 判断

age = 3
if age>= 18:
    print("adult")

elif age >= 6:
    print("teenager")
else: 
    print("kids")

print("your age is", age)

# 转换成 int

birth = input('birth: ')
birth = int(birth)
if birth < 2000:
    print("00qian")
else:
    print("00hou")

# 循环

sum = 0
for x in list(range(5)):
    sum = sum + x
print(sum)

alphobets = ['a','b','c']
for char in alphobets:
    print(char)

names = ['michael', 'bob', 'Tracy']
for name in names:
    print(name)

sum = 0
i = 0
while(i<101):
    sum += i
    i += 1
print(sum)

L = ['Bart', 'Lisa', 'Adam']
for name in L:
    print("hello, %s!" % name)

# 字典 dictionary

d = {'Michael':95, 'Bob':75, 'Tracy':85}
d['Adam'] = 67
print(d['Adma'])

# 函数

def myabs(x):
    if not isinstance(x, (int, float)):
        raise TypeError('bad operand type')
    if x>=0:
        return x
    else:
        return -x

print(myabs(111))

# 函数返回元组

import math

def move(x, y, step, angle=0):
    nx = x + step * math.cos(angle)
    ny = y + step * math.sin(angle)
    return nx, ny

# 分别赋给每个变量

x, y = move(100,100,60,math.pi/6)
print(x,y)

def quadratic(a,b,c):
    delta = b*b - 4*a*c
    x1 = (-b + math.sqrt(delta)) / (2 * a)
    x2 = (-b - math.sqrt(delta)) / (2 * a)
    return x1, x2

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')


#def power(x):
   # return x * x

# 默认参数

def power(x,n=2):
    s = 1
    while n > 0:
        n = n - 1
        s = s * x
    return s

print(power(5))
print(power(5,3))

# 可变长度参数

def clac(*numbers):
    sum = 0
    for n in numbers:
        sum = sum + n * n
    return sum

print(clac(1,2))
print(clac())

# 递归：汉诺塔
# 参数n，表示初始时，3个柱子a、b、c中第1个柱子a上的盘子数量，
# 打印出把所有盘子从A借助B移动到C的方法
def move(n, a, b, c):
    if n == 1:
        print(a, '-->', c)
    else:
        move(n-1,a,c,b)
        print(a,'-->',c)
        move(n-1,b,a,c)
    return

move(3,'A','B','C')