python3常见操作

 

 布尔操作，是或者否：

Operation

Result

Notes

x or y	if x is false, then y, else x	(1)
x and y	if x is false, then x, else y	(2)
not x	if x is false, then True, else False	(3)

 

比较操作，大还是小，是否相同对象，是否相同值：

Operation

Meaning

<	strictly less than
<=	less than or equal
>	strictly greater than
>=	greater than or equal
==	equal
!=	not equal
is	object identity
is not	negated object identity

 

常用数学计算：

Operation

Result

Notes

Full documentation

x + y	sum of x and y
x - y	difference of x and y
x * y	product of x and y
x / y	quotient of x and y
x // y	floored quotient of x and y	(1)
x % y	remainder of x / y	(2)
-x	x negated
+x	x unchanged
abs(x)	absolute value or magnitude of x		abs()
int(x)	x converted to integer	(3)(6)	int()
float(x)	x converted to floating point	(4)(6)	float()
complex(re, im)	a complex number with real part re, imaginary part im. im defaults to zero.	(6)	complex()
c.conjugate()	conjugate of the complex number c
divmod(x, y)	the pair (x // y, x % y)	(2)	divmod()
pow(x, y)	x to the power y	(5)	pow()
x ** y	x to the power y	(5)

 

字符串常见操作：

Operation

Result

Notes

x in s	True if an item of s is equal to x, else False	(1)
x not in s	False if an item of s is equal to x, else True	(1)
s + t	the concatenation of s and t	(6)(7)
s * n or n * s	equivalent to adding s to itself n times	(2)(7)
s[i]	ith item of s, origin 0	(3)
s[i:j]	slice of s from i to j	(3)(4)
s[i:j:k]	slice of s from i to j with step k	(3)(5)
len(s)	length of s
min(s)	smallest item of s
max(s)	largest item of s
s.index(x[, i[, j]])	index of the first occurrence of x in s (at or after index i and before index j)	(8)
s.count(x)	total number of occurrences of x in s

 

 

数组常见操作：

Operation

Result

Notes

s[i] = x	item i of s is replaced by x
s[i:j] = t	slice of s from i to j is replaced by the contents of the iterable t
del s[i:j]	same as s[i:j] = []
s[i:j:k] = t	the elements of s[i:j:k] are replaced by those of t	(1)
del s[i:j:k]	removes the elements of s[i:j:k]from the list
s.append(x)	appends x to the end of the sequence (same as s[len(s):len(s)] = [x])
s.clear()	removes all items from s (same as del s[:])	(5)
s.copy()	creates a shallow copy of s (same as s[:])	(5)
s.extend(t) or s += t	extends s with the contents of t (for the most part the same ass[len(s):len(s)] = t)
s *= n	updates s with its contents repeated n times	(6)
s.insert(i, x)	inserts x into s at the index given by i(same as s[i:i] = [x])
s.pop([i])	retrieves the item at i and also removes it from s	(2)
s.remove(x)	remove the first item from s where s[i] is equal to x	(3)
s.reverse()	reverses the items of s in place	(4)

 

常见格式化占位符：

Conversion

Meaning

Notes

'd'	Signed integer decimal.
'i'	Signed integer decimal.
'o'	Signed octal value.	(1)
'u'	Obsolete type – it is identical to 'd'.	(6)
'x'	Signed hexadecimal (lowercase).	(2)
'X'	Signed hexadecimal (uppercase).	(2)
'e'	Floating point exponential format (lowercase).	(3)
'E'	Floating point exponential format (uppercase).	(3)
'f'	Floating point decimal format.	(3)
'F'	Floating point decimal format.	(3)
'g'	Floating point format. Uses lowercase exponential format if exponent is less than -4 or not less than precision, decimal format otherwise.	(4)
'G'	Floating point format. Uses uppercase exponential format if exponent is less than -4 or not less than precision, decimal format otherwise.	(4)
'c'	Single character (accepts integer or single character string).
'r'	String (converts any Python object using repr()).	(5)
's'	String (converts any Python object using str()).	(5)
'a'	String (converts any Python object using ascii()).	(5)
'%'	No argument is converted, results in a '%' character in the result.