#求根公式 x = (-b±√(b²-4ac)) / 2a
import math
def quadratic_equation(a, b, c):
#求平方根的方法
t = math.sqrt(b * b - 4 * a * c)
return (-b + t) / (2 * a),( -b - t )/ (2 * a)
print quadratic_equation(2, 3, 0)
print quadratic_equation(1, -6, 5)
#参数设置默认值
def method(arg = 1):
print 1
method()
#定义可变参数
def average(*args):
sum = 0.0
if len(args) == 0:
return sum
for x in args:
sum = sum + x
return sum / len(args)
print average()
print average(1, 2, 2, 3, 4)
#获取0到100 list
myList = range(0,100)
#list切片 截取
#通过索引 获取2 到 20
print myList[2:30]
#获取索引位置为2的 到 倒排索引95 的所有
print myList[2:-95]
#获取从2到6 每隔两个获取一次
print myList[2:6:2]
#重新赋值
newList = myList[:]
print newList
#遍历list 通过enumerate()自动为每个元素赋值索引
L = ['Adam', 'Lisa', 'Bart', 'Paul']
for index, name in enumerate(L):
print index, '-', name
#将两个list拼接成dict
print zip([10, 20, 30], ['A', 'B', 'C']) #[(10, 'A'), (20, 'B'), (30, 'C')]
#通过迭代器 遍历dict 获取value
d = { 'Adam': 95, 'Lisa': 85, 'Bart': 59, 'Paul': 74 }
sum = 0.0
for v in d.itervalues():
sum = sum + v
print sum / len(d)
#默认遍历时获取的是key
for key in d:
print key
print d[key]
#迭代器获取 每个 (java)entry
sum = 0.0
for k, v in d.iteritems():
sum = sum + v
print k, ':', v
print 'average', ':', sum / len(d)
#列表生成式 生成水仙花数 for嵌套加 if条件判断
print [100 * n1 + 10 * n2 + n3 for n1 in range(1, 10) for n2 in range(10) for n3 in range(10) if n1==n3]
#通过占位符生成table标签
d = { 'Adam': 95, 'Lisa': 85, 'Bart': 59 }
def generate_tr(name, score):
if score < 60:
return '<tr><td>%s</td><td style="color:red">%s</td></tr>' % (name, score)
return '<tr><td>%s</td><td>%s</td></tr>' % (name, score)
tds = [generate_tr(name, score) for name, score in d.iteritems()]
print '<table border="1">'
print '<tr><th>Name</th><th>Score</th><tr>'
print '\n'.join(tds)
print '</table>'