Python技法-序列拆分详解

p = (4, 5)
x, y = p 
print(x, y) # 4 5

x, y, z = p

p = (4, 5, 6)
x, y = p

s = 'Hello'
a, b, c, d, e = s
print(a) # H

s = 'Hello'
a, b, _, d, _ = s
print(a) # H

data = ['zhy', 50, 123.0, (2000, 12, 21)]
name, shares, price, (year, month, day) = data
print(year) # 2000

data = ['zhy', 50, 123.0, (2000, 12, 21)]
name, shares, price, date = data
print(date) # (2000, 12, 21)

def avg(data: list):
    return sum(data)/len(data)
# 去掉最高分，最低分然后做均分统计
def drop_first_last(grades):
    first, *middle, last = grades
    return avg(middle)
print(drop_first_last([1,2,3,4])) # 2.5

record = ['zhy', 'zhy1056692290@qq.com', '773-556234', '774-223333']
name, email, *phone_numbers = record
print(phone_numbers) # ['773-556234', '774-223333']

record = ['zhy', 'zhy1056692290@qq.com']
name, email, *phone_numbers = record
print(phone_numbers) # []

records = [('foo', 1, 2), ('bar', 'hello'), ('foo', 3, 4)]
for tag, *args in records:
    if tag == 'bar':
        print(args)
# ['hello']

line = "nobody:*:-2:-2:-2:Unprivileged User:/var/empty:/usr/bin/false"
uname, *fields, home_dir, sh = line.split(':')
print(home_dir) # /var/empty

record = ['ACME', 50, 123.45, (128, 18, 2012)]
name, *_, (*_, year) = record
print(year) # 2012

items = [1, 10, 7, 4, 5, 9]
def sum(items):
    head, *tail = items
    return head + sum(tail) if tail else head
print(sum(items)) # 36