1.abs取絕對值
>>> abs(9.8)
9.8
>>> abs(-9.8)
9.8
2.dic()變為字典類型
>>> dict({"key":"value"})
{'key': 'value'}
3.help()顯示幫助資訊
>>> 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
-- More --
4.min取資料中的最小值，max取資料中的最大值
print(min([3, 4, 2]))
print(min("wqeqwe"))
print(min((3, 6, 4)))
print(max([3, 4, 2]))
print(max("wqeqwe"))
print(max((3, 6, 4)))
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
2
e
3
4
w
6
Process finished with exit code 0
5.all()所有的為true，才傳回true。空的清單傳回true
print(all([1, 2, 0])) # 清單中的0是False,是以傳回False
print(all([1, 2, 5])) # 清單中的所有值都是True,是以傳回True
print(all([])) # 空的清單，all()傳回true
print(help(all))
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
False
True
True
Help on built-in function all in module builtins:
all(iterable, /)
Return True if bool(x) is True for all values x in the iterable.
If the iterable is empty, return True.
None
Process finished with exit code 0
6.any()任意一個為true就傳回true。空的清單傳回false
any()清單中的任意一個為True，就傳回True
print(any([1, 2, 0]))
print(any([1, 2, 5])) # 清單中的任意一個是True,就傳回True
print(any([])) # 空的清單，any()傳回false
print(help(any))
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
True
True
False
Help on built-in function any in module builtins:
any(iterable, /)
Return True if bool(x) is True for any x in the iterable.
If the iterable is empty, return False.
None
Process finished with exit code 0
7.dir()列印目前程式的所有變量
print(dir()) # 列印目前程式的所有變量
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__']
Process finished with exit code 0
8.hex()把十進制數轉換為16進制數
hex()轉換為16進制
print(hex(16))
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
0x10
Process finished with exit code 0
9.slice()切片
>>> l = [2,3,4,5,6,7]
>>> s = slice(1,5,2)
>>> l(s)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'list' object is not callable
>>> l[s]
[3, 5]
10.divmod()求商和餘數
>>> divmod(10,3)
(3, 1)
>>> divmod(10,2)
(5, 0)
>>>
11.sorted()排序
>>> sorted([1,9,4])
[1, 4, 9]
d = {1: 0, 10: 4, 9: 2, 15: 3}
print(d.items())
print(sorted(d.items(), key=lambda x: x[1], reverse=True))
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
dict_items([(1, 0), (10, 4), (9, 2), (15, 3)])
[(10, 4), (15, 3), (9, 2), (1, 0)]
Process finished with exit code 0
13.ascii()轉換為ascii碼
>>> ascii("qwqw我")
"'qwqw\\u6211'"
14.oct()十進制數轉換為8進制數
>>> print(oct(8))
0o10
15.bin()十進制數轉換為二進制數
>>> print(bin(10))
0b1010
16.eval()把字元轉換為裡面原有的含義，把字元串轉換為代碼
print(eval("{1:2}"))
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
{1: 2}
Process finished with exit code 0
print(eval("1+2*3"))
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
7
Process finished with exit code 0
eval('print("hello")')
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
hello
Process finished with exit code 0
eval()隻能解析單行代碼，不能解析多行的代碼
code = '''
if 3 > 2:
print("3>2")
'''
eval(code)
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
Traceback (most recent call last):
File "E:/PythonProject/python-test/BasicGrammer/test.py", line 9, in <module>
eval(code)
File "<string>", line 2
if 3 > 2:
^
SyntaxError: invalid syntax
Process finished with exit code 1
17.exec()可以解析執行多行代碼，但是擷取不到函數的傳回值，eval()可以
code = '''
if 3 > 2:
print("3>2")
'''
exec(code)
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
3>2
Process finished with exit code 0
code = '''
def foo():
if 3 > 2:
print("3>2")
return 3
foo()
'''
re_exec = exec(code)
print(re_exec)
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
3>2
None
Process finished with exit code 0
print(eval("1+2+3"))
print(exec("1+2+3"))
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
6
None
Process finished with exit code 0
18.ord()擷取對應的ascii碼表中的值。chr()擷取ascii表中對應的字元
ord() 擷取對應的ascii碼表中的值
chr() 擷取ascii表中值對應的字元
>>> ord("a")
97
>>> chr(97)
'a'
19.sum()求和
>>> sum((1,2,3))
6
>>> sum([1,2,3])
6
>>> sum({1:2,3:4})
4
>>> sum({1,2,3,4})
10
>>> sum("123")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for +: 'int' and 'str'
>>>
20.bytearray()可通過encode,decode之後，通過index來修改字元串中的值
>>> s = "woai中國"
>>> s[0] = "W"
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'str' object does not support item assignment
>>> s = bytearray(s)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: string argument without an encoding
>>> s = s.encode('utf-8')
>>> s
b'woai\xe4\xb8\xad\xe5\x9b\xbd'
>>> s = bytearray(s)
>>> s
bytearray(b'woai\xe4\xb8\xad\xe5\x9b\xbd')
>>> s[0]='W'
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: an integer is required
>>> s[0]=97
>>> s
bytearray(b'aoai\xe4\xb8\xad\xe5\x9b\xbd')
>>> s.decode('utf-8')
'aoai中國'
21.id()檢視變量的記憶體位址
>>> id(s[0]) # s[0]的記憶體位址會變
1487327920
>>> s[0]=66
>>> id(s[0])
1487326928
>>> id(s)
2879739806752 # s的記憶體位址是不變的
>>> s[0]=67
>>> id(s)
2879739806752
22.map()通過匿名函數lambda來對清單中的資料進行操作
map()
>>> list(map(lambda x:x*x,[1,2,3]))
[1, 4, 9]
filter()
>>> list(filter(lambda x:x>3,[1,2,3,4,5]))
[4, 5]
23.reduce()對資料進行整合操作，傳回一個值
>>> import functools
>>> functools.reduce(lambda x,y:x+y,[1,2,3,4])
10
>>> functools.reduce(lambda x,y:x*y,[1,2,3,4])
24
>>> functools.reduce(lambda x,y:x*y,[1,2,3,4],2)
48
>>> functools.reduce(lambda x,y:x*y,[1,2,3,4],3)
72
>>> functools.reduce(lambda x,y:x+y,[1,2,3,4],3)
13
24.print()
def print(self, *args, sep=' ', end='\n', file=None): # known special case of print
"""
print(value, ..., sep=' ', end='\n', file=sys.stdout, flush=False)
Prints the values to a stream, or to sys.stdout by default.
Optional keyword arguments:
file: a file-like object (stream); defaults to the current sys.stdout.
sep: string inserted between values, default a space.
end: string appended after the last value, default a newline.
flush: whether to forcibly flush the stream.
"""
pass
#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author: vita
msg = "msg"
# 檔案的模式必須是可寫入模式（w,r+），不能是隻讀模式
f = open(file="寫檔案.txt", mode="w", encoding="utf-8")
print(msg, "my input", sep="|", end=":::",file=f)
運作程式
E:\PythonProject\python-test\venvP3\Scripts\python.exe E:/PythonProject/python-test/BasicGrammer/test.py
Process finished with exit code 0
檢視"寫檔案.txt"
msg|my input:::
25.tupple()把可疊代的資料類型變為元組
>>> a = [1,2,3]
>>> tuple(a)
(1, 2, 3)
>>> tuple("1,2,3")
('1', ',', '2', ',', '3')
>>> tuple({1:2})
(1,)
>>> tuple(2)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'int' object is not iterable
26.callable()判斷是否可調用，即通過abs()方式調用，函數是可調用的，可用于判斷是否是函數
callable()判斷是否可調用，即通過abc()方式調用
函數是可調用的，可用于判斷是否是函數
>>> callable(abs)
True
>>> callable(list)
True
>>> callable([1,2,3])
False
27.frozenset()變為不可變集合
>>> s = frozenset({1,2,3})
>>> s.discard(2)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'frozenset' object has no attribute 'discard'
28.vars()包含變量的名和變量的值，dir()隻是變量的名字
>>> vars()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_import
lib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins'
(built-in)>, 'l': [2, 3, 4, 5, 6, 7], 's': bytearray(b'aoaini'), 'd': {10: 2, 12: 1, 9: 0}, 'a': [1
, 2, 3]}
['__annotations__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__',
'a', 'd', 'l', 's']
>>>
29.locals()列印局部變量，globals()列印全局變量
>>> globals()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_import
lib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'l': [2, 3, 4, 5, 6, 7], 's': bytearray(b'aoaini'), 'd': {10: 2, 12: 1, 9: 0}, 'a': [1, 2,
3]}
>>> locals()
{'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (bui
lt-in)>, 'l': [2, 3, 4, 5, 6, 7], 's': bytearray(b'aoaini'), 'd': {10: 2, 12: 1, 9: 0}, 'a': [1, 2, 3]}
>>>
30.repr顯示形式變為字元串
>>> repr(abs(23))
'23'
>>> repr(frozenset({12,4}))
'frozenset({12, 4})'
>>> repr({1,2,3})
'{1, 2, 3}'
>>>
31.zip
>>> a = [1,2,3,4,5]
>>> b = ["a","b","c"]
>>> zip(a)
<zip object at 0x00000237FF9EAF08>
>>> zip(a,b)
<zip object at 0x00000237FF9D8448>
>>> list(zip(a,b))
[(1, 'a'), (2, 'b'), (3, 'c')]
>>> dict(zip(a,b))
{1: 'a', 2: 'b', 3: 'c'}
>>> str(zip(a,b))
'<zip object at 0x00000237FF9EAF08>'
>>> tuple(zip(a,b))
((1, 'a'), (2, 'b'), (3, 'c'))
>>>
32.complex()變為複數
>>> complex(3,5)
(3+5j)
>>> complex(3)
(3+0j)
33.round()保留幾位小數位
>>> round(3.12123333333334444445555555555555555,18)
3.1212333333333446
>>> round(3.12123333333334444445555555555555555,2)
3.12
34.hash()把字元串變為固定長度的hash值
不可變資料類型才是可hash的，包含整數，字元串，元組，都是不可變的，是可hash的
>>> hash("12")
8731980002792086209
>>> hash("123")
-1620719444414375290
>>> hash([1,2])
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'
>>> hash(1)
1
>>> hash(123)
123
>>> hash((1,2))
3713081631934410656
>>> hash((1,2,3))
2528502973977326415
>>> hash({1,2,3})
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'set'
>>>
35.set()把可疊代對象變為集合集合
>>> set([1,2,3])
{1, 2, 3}
>>> set((1,2,3))
{1, 2, 3}
>>> set("21")
{'1', '2'}
>>> set(2)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'int' object is not iterable
>>> set({1:2,3:4})
{1, 3}
>>>
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