pythonベース-組み込み関数-役割ドメイン-閉パッケージ-再帰-python 3
組み込み関数-役割ドメイン-閉パッケージ-再帰
1.使用可能ないくつかの組み込み関数
2.関数内変数の役割ドメイン
3.埋め込み関数と閉パッケージ
4.再帰
1.使用可能ないくつかの組み込み関数
：
print(dir(__builtins__))
：
len
min
max
sorted ，
reversed
sum
：
bin()
oct()
hex()
ord() ASIIC
chr() ASIIC
：
1.enumerate()
2.filter()
3.map() 。 iterable fuction ， map
4.zip()
1.1 ：
>>> help(sum)
Help on built-in function sum in module builtins：
sum(iterable, start=0, /)
Return the sum of a 'start' value (default: 0) plus an iterable of numbers
When the iterable is empty, return the start value.
This function is intended specifically for use with numeric values and may
reject non-numeric types.
>>> sum((1,23,4))
28
>>> sum([1,2,3])
6
>>> sum([1,2,3],10)
16
>>> sum([10,20,30],20) # =iterable +start
80
>>> sum([10,20,30],22) # =iterable +start
82
>>> sum({1:12,2:30}) #key
3
1.2 ：
>>> bin(1)
'0b1'
>>> bin(2)
'0b10'
1.3 ：
>>> oct(8)
'0o10'
>>> oct(12)
'0o14'
1.4 ：
>>> hex(10)
'0xa'
>>> hex(9)
'0x9'
>>> hex(15)
'0xf'
1.5 ASIIC
>>> chr(65)
'A'
>>> chr(32)
' '
1.6 ASIIC
>>> ord('a')
97
>>> ord(' ')
32
1.7 enumerate:
>>> help(enumerate)
Help on class enumerate in module builtins:
class enumerate(object)
| enumerate(iterable[, start]) -> iterator for index, value of iterable
|
| Return an enumerate object. iterable must be another object that supports
| iteration. The enumerate object yields pairs containing a count (from
| start, which defaults to zero) and a value yielded by the iterable argument.
| enumerate is useful for obtaining an indexed list:
| (0, seq[0]), (1, seq[1]), (2, seq[2]), ...
|
| Methods defined here:
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __iter__(self, /)
| Implement iter(self).
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __next__(self, /)
| Implement next(self).
|
| __reduce__(...)
| Return state information for pickling.
>>> enumerate([1,2,3,4])
#
>>> list(enumerate([1,2,3,4])) #
[(0, 1), (1, 2), (2, 3), (3, 4)] # ，index 0，
>>> list(enumerate(['a','b','c','d']))
[(0, 'a'), (1, 'b'), (2, 'c'), (3, 'd')] # ，index 0，
>>> list(enumerate(['a','b','c','d'],3))
[(3, 'a'), (4, 'b'), (5, 'c'), (6, 'd')]
>>> list(enumerate((1,23,4,5,6),3))
[(3, 1), (4, 23), (5, 4), (6, 5), (7, 6)]
>>> list(enumerate({1,2,3,4,5},3)) #
[(3, 1), (4, 2), (5, 3), (6, 4), (7, 5)]
>>> list(enumerate({1:2,2:3,3:4},3)) #
[(3, 1), (4, 2), (5, 3)]
1.8 filter
>>> help(filter)
Help on class filter in module builtins：
class filter(object)
| filter(function or None, iterable) --> filter object
| Return an iterator yielding those items of iterable for which function(item)
| is true. If function is None, return the items that are true.
| Methods defined here:
| __getattribute__(self, name, /)
| Return getattr(self, name).
| __iter__(self, /)
| Implement iter(self).
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
| __next__(self, /)
| Implement next(self).
| __reduce__(...)
| Return state information for pickling.
>>> filter(lambda x:x>2,[1,2,3,4,5]) #lambda x:x>2
#
>>> list(filter(lambda x:x>2,[1,2,3,4,5]))
[3, 4, 5]
>>> list(filter(None,[1,2,3,4,5]))
[1, 2, 3, 4, 5]
1.9 map
>>> help(map)
Help on class map in module builtins:
class map(object)
| map(func, *iterables) --> map object
| Make an iterator that computes the function using arguments from
| each of the iterables. Stops when the shortest iterable is exhausted.
| Methods defined here:
| __getattribute__(self, name, /)
| Return getattr(self, name).
| __iter__(self, /)
| Implement iter(self).
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
| __next__(self, /)
| Implement next(self).
| __reduce__(...)
| Return state information for pickling.
>>> list(map(str,[1,2,3,4]))
['1', '2', '3', '4']
1.10 zip
>>> list(zip([1,2,3],[4,5,6]))
[(1, 4), (2, 5), (3, 6)]
>>> list(zip((1,2,3),(4,5,6)))
[(1, 4), (2, 5), (3, 6)]
>>> list(zip([1,2,3],(4,5,6)))
[(1, 4), (2, 5), (3, 6)]
>>> list(zip([1,2,3,4],[5,6,7,8,9],['a','b']))
[(1, 5, 'a'), (2, 6, 'b')] 2.関数内変数の役割ドメイン
：
： ，
： ，
global： ， .( )
nonlocal: ， ( ) 。( )
global ：
，
， global
， ， global，
nonlocal ：
， ， nonlocal。( ： )
：
global： ，
nonlocal： ， ， 。( ， nonlocal)
2.1 、
x=1 # ， ，
def fun():
y=2 #
print(x,y)
2.2 ， global
x=1
def fun():
global x #
x += 1
print(x)
2.3 ， global
def fun():
global x
x = 1
print(x)
2.4
def test():
a=1 #
print(a)
def test2():
b=2 #
print(a,b)
test2() # ， test()。test2()
>>> test()
1
1 2
2.5 ：
def test():
a=1 #
print(a)
def test2():
b=2 #
nonlocal a #
a += 1 #
print(a,b)
test2()
>>> test()
1
2 23.埋め込み関数と閉パッケージ
：
def test():
a=1
print(a)
def test2():
b=2
nonlocal a
a += 1
print(a,b)
test2() #
：
def test():
a=1
print(a)
def test2():
b=2
print(b)
return test2 # -
>>> test()
1
.test2 at 0x00000000005B7F28>
：
def test1():
print('first')
def fun(a):
a()
print('two')
fun(test1)
================== RESTART: C:\Users\xinyu\Desktop\test.py ==================
first
two 4.再帰
'''
： 5 ， ？ 4 2 。
4 ， 3 2 。
， 2 。
2 ， 。
， 10 。
？
'''
：
1.
2.
def age(n):
if n == 1:
return 10
else:
return age(n-1)+2
： 5！=5*4*3*2*1
#n != n*(n-1)*(n-2)*....1
def jicheng(n):
if n == 1:
return 1
else:
return jicheng(n-1)*n