函数小练习

# (1)
name = ['oldboy', 'alex', 'wusir']
def func(n):	
	return n+"_leader"
	
# map 返回迭代器
# None 地址 容器 迭代器 map(func,name)
it = map(func,name)
print(list(it))

# 匿名函数
it = map(lambda n : n+'_leader',name)
print(list(it))


# 2.用map来处理下述 listvar ,要求得到新列表,每个元素名字加后面加_leader
# listvar = [{'name':'alex'},{'name':'wusir'}]
listvar = [{'name':'alex'},{'name':'wusir'}]
def func(n):
	# n = {'name':'alex'}
	return n['name'] + "_leader"
	
it = map(func,listvar)
print(list(it))

it = map(lambda n : n['name'] + "_leader",listvar)
print(list(it))

# 3.用filter来处理,得到股票价格大于20的股票名字
shares={
   	'IBM':36.6,
   	'Lenovo':23.2,
  	'oldboy':21.2,
    'ocean':10.2,
	}

def func(n):
	# n => IBM Lenovo oldboy ocean
	# return shares[n] 
	if shares[n] > 20:
		return True	
it = filter(func,shares)
print(list(it))

# 匿名函数
it = filter(lambda n : True if shares[n] > 20 else False , shares)
print(list(it))
"""
4.有下面字典:
"""
portfolio=[
	{'name':'IBM','shares':100,'price':91.1},
	{'name':'AAPL','shares':20,'price':54.0},
	{'name':'FB','shares':200,'price':21.09},
	{'name':'HPQ','shares':35,'price':31.75},
	{'name':'YHOO','shares':45,'price':16.35},
	{'name':'ACME','shares':75,'price':115.65}
]
# a.获取购买每只股票的总价格(乘积),迭代器中[9110.0, 1080.0 ,......]
# b.用filter过滤出price大于100的股票。1
# (a)
def func(n):
	# n =>{'name':'IBM','shares':100,'price':91.1}
	return n['shares'] * n['price']

it = map(func,portfolio)
print(list(it))

# 匿名函数
it = map(lambda n : n['shares'] * n['price'],portfolio)
print(list(it))

#(b)
def func(n):
	if n['price'] > 100:
		return True

it = filter(func,portfolio)
print(list(it))

# 匿名函数
it = filter(lambda n : True if n['price'] > 100 else False,portfolio)
print(list(it))

# 5. 
listvar = [
	{'sales_volumn': 0},
	{'sales_volumn': 108},
	{'sales_volumn': 337},
	{'sales_volumn': 475},
	{'sales_volumn': 396},
	{'sales_volumn': 172},
	{'sales_volumn': 9},
	{'sales_volumn': 58},
	{'sales_volumn': 272},
	{'sales_volumn': 456},
	{'sales_volumn': 440},
	{'sales_volumn': 239}
]

# 将 listvar 按照列表中的每个字典的values大小进行排序,形成一个新的列表。
def func(n):
	# n {'sales_volumn': 0}
	return n['sales_volumn']
lst = sorted(listvar,key=func)	
print(lst)
'''
{'sales_volumn': 0} => 0
{'sales_volumn': 108} => 108
{'sales_volumn': 337} => 337
...
...
依次类推:按照values排序,之后对列表排序
'''

# 匿名函数
lst= sorted(listvar,key=lambda n : n['sales_volumn'] )
print(lst)