序列组成的数组是如何定义的？

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python列表推导生成T恤组合colors=['block', 'white']sizes=['s', 'n', 'l']tshirts=[(color, size) for color in colors for size in sizes]print(tshirts)

列表推导，笛卡尔乘积

colors = ['block','white']
sizes = ['s','n','l']

tshirts = [(color,size) for color in colors for size in sizes]
print(tshirts)

[('block', 's'), ('block', 'n'), ('block', 'l'), ('white', 's'), ('white', 'n'), ('white', 'l')]

元祖不仅仅是不可变的列表

元组和记录

lax_coordinates = (32.9425,-118.405689)
city,year,pop,chg,area = ('tokyo',2003,32450,0.66,8014)

traveler_ids = [('usa','31195855'),('bra','ce342567'),('esp','xda205856')]
for passport in sorted(traveler_ids):
print('%s/%s' % passport)

for country,_ in traveler_ids:
print(country)C:\Python\python3.6.5\python.exe E:/pythoncode/day07/01.py
bra/ce342567
esp/xda205856
usa/31195855
usa
bra
esp

元组拆包

lax_coordinates = (32.5985,-118.4582556)
lat,lng = lax_coordinates
print(lat)
print(lng)

还可以用*把一个可迭代对象拆开作为函数的参数

print(divmod(20,8))
#(2, 4)
t=(20,8)
q,r=divmod(*t)
print(q,r)
#2 4

a,b,*reset = range(5)
print(a,b,reset)

具名元组

from collections import namedtuple

City = namedtuple('City',('name','country','popolation','coordinates'))
tokyo = City('Tokyo','jp','36.933',(35.6,139.66))
print(tokyo)
#City(name='Tokyo', country='jp', popolation='36.933', coordinates=(35.6, 139.66))

print(tokyo.popolation)
#36.933

print(City._fields)
#('name', 'country', 'popolation', 'coordinates')

latlong = namedtuple('latlong','lat long')
delhi_data = ('delhi ncr' , 'in',21.935,latlong(28.36,77.69))
delhi = City._make(delhi_data)
print(delhi)
#City(name='delhi ncr', country='in', popolation=21.935, coordinates=latlong(lat=28.36, long=77.69))

print(delhi._asdict())
#OrderedDict([('name', 'delhi ncr'), ('country', 'in'), ('popolation', 21.935), ('coordinates', latlong(lat=28.36, long=77.69))])