Python basis (day04)
Basic data types
Digital Type
Action: storing digital, or mathematical operation for counting
Defined manner: a = 1; a = int (1)
Usage: + Addition - Subtraction * Multiplication /% // modulo a power of other rounding **
String type
Role: storing character
Defined method: s = 'str'; s = '' str ''; s = '' 'str' ''; s = str ( 'str')
Usage: string can be added between the
And may be represented by a number n * string with repeated n times
List
Action: as a container for storing a plurality of elements, the elements may be different data types
Defined manner: a = [1,2,3,4,5,6, 'a', 8]
a=list('handsome sheppard')
Usage: a = list ( 'handsome sheppard')
a[:2]=>['h', 'a']
a[-4:]=>['p', 'a', 'r', 'd']
dictionary
Action: key index may be (key may be integer, floating point, tuple, string) value storage, can store a plurality of key: value element
Defined method: dic = {key: value}
Usage: dic = {}
dic['name']='sheppard'
print(dic)====》{'name': 'sheppard'}
Boolean
Action: determination logic
Defined method: bol = True; bol = bool (1)
Usage: print (1 == 2) == "False
In addition to the python 0 / None / null / False values of all comes with Boolean True
Decompression operation
If we give a list lis = [ 'sheppard', 'male', '180'], we need to remove a plurality of disposable values, which requires use of a decompression operation.
name_list = ['sheppard', 'male', '180']
x = name_list[0]
y = name_list[1]
z = name_list[2]
print(f'x:{x}, y:{y}, z:{z}'==>x:sheppard,y:male,z:180
If only part of the time needed, some values are not what we want, then use universal underscore
lis = ['sheppard', 'male', '180']
_,y,z=lis ==>y='male';z='180'
* _ Represents may also be used in the whole process will be omitted
*_,z=lis==>z='180'
== Also note that the dictionary can also decompress, but decompression is key ==
info={'name':'sheppard','sex':'male','height':'180','weight':'160'}
a,b,c,d=info==>a='name';b='sex';c='height';d='weight'