Python development "full stack-day-iv": python basic data type

Operator 1. Arithmetic operation:

2. Comparison operation:

3. Assignment operation:

4. Logical Operation:

5. Member Arithmetic:

Basic data types 1. Digital

int (integral Type)

On a 32-bit machine, the number of integers is 32 bits and the value range is -2**31~2**31-1, which is -2147483648~2147483647
On a 64-bit system, the number of integers is 64 bits and the value range is -2**63~2**63-1, which is -9223372036854775808~9223372036854775807int 2. Boolean valueTrue or False 1 or 0 3. String

"hello world"

String Common Functions:

• Remove whitespace
• Segmentation
• Length
• Index
• Slice

Str 4. ListTo create a list:

123	name_list =[‘alex‘, ‘seven‘, ‘eric‘]或name_list ＝ list([‘alex‘, ‘seven‘, ‘eric‘])

Basic Operation:

• Index
• Slice
• Additional
• Delete
• Length
• Slice
• Cycle
• Contains

List 5, GansoTo create a meta-ancestor:

123	ages =(11, 22, 33, 44, 55)或ages =tuple((11, 22, 33, 44, 55))

Basic Operation:

• Index
• Slice
• Cycle
• Length
• Contains

Lass tuple (object): "" "tuple (), empty tuple tuple (iterable), tuple initialized from iterable ' s items    If The argument is a tuple, the return value is the same object. "" "def Count (self, value): # Real Signature unknown;     Restored from __doc__ "" "t.count (value)--return Number of occurrences of value" "" return 0 def index (self, value, start=none, stop=none): # Real Signature unknown;        Restored from __doc__ "" "t.index (value, [start, [stop]), integer-return First Index of Value.        Raises valueerror if the value is not present. "" "return 0 def __add__ (self, y): # Real Signature unknown; Restored from __doc__ "" "x.__add__ (y) <==> x+y" "" pass def __contains__ (self, y): # real Signatur E unknown; Restored from __doc__ "" "x.__contains__ (y) <==> y in x" "" pass def __eq__ (self, y): # Real Signat Ure unknown; Restored from __doc__ """ x.__eq__ (y) <==> x==y "" "pass def __getattribute__ (self, name): # Real Signature unknown;  Restored from __doc__ "" "x.__getattribute__ (' name ') <==> x.name" "" pass def __getitem__ (self, y): # Real Signature unknown; Restored from __doc__ "" "x.__getitem__ (y) <==> x[y]" "" pass def __getnewargs__ (self, *args, **kwa Rgs): # Real Signature Unknown pass def __getslice__ (self, i, j): # Real Signature unknown;  Restored from __doc__ "" "x.__getslice__ (i, j) <==> x[i:j] use of        Negative indices is not supported. "" "pass def __ge__ (self, y): # Real Signature unknown; Restored from __doc__ "" "x.__ge__ (y) <==> x>=y" "" pass def __gt__ (self, y): # Real Signature U nknown; Restored from __doc__ "" "x.__gt__ (y) <==> x>y" "" pass def __hash__ (self): # Real Signature UNK nown;       Restored from __doc__ "" "x.__hash__ () <==> Hash (x)" "" pass def __init__ (self, seq= ()): # Known special case of tuple.__init__                "" "tuple (), Empty tuple tuple (iterable), tuple initialized from iterable ' s items        If The argument is a tuple, the return value is the same object. # (copied from class Doc) "" "pass def __iter__ (self): # Real Signature unknown; Restored from __doc__ "" "x.__iter__ () <==> iter (x)" "" pass def __len__ (self): # real Signature UN known; Restored from __doc__ "" "x.__len__ () <==> len (x)" "" pass def __le__ (self, y): # Real Signature UN known; Restored from __doc__ "" "x.__le__ (y) <==> x<=y" "" pass def __lt__ (self, y): # Real Signature U nknown; Restored from __doc__ "" "x.__lt__ (y) <==> x<y" "" pass def __mul__ (self, n): # Real Signature U nknown; Restored from __doc__ "" "x.__mul__ (n) <==> x*n"" "pass @staticmethod # known case of __new__ def __new__ (S, *more): # Real Signature unknown; Restored from __doc__ "" "t.__new__ (S, ...) A new object with type S, a subtype of T "" "pass def __ne__ (self, y): # Real Signature unknown; Restored from __doc__ "" "x.__ne__ (y) <==> x!=y" "" pass def __repr__ (self): # Real Signature Unkno Wn Restored from __doc__ "" "x.__repr__ () <==> repr (x)" "" pass def __rmul__ (self, n): # real Signatur E unknown; Restored from __doc__ "" "x.__rmul__ (n) <==> n*x" "" pass def __sizeof__ (self): # real Signature UN known; Restored from __doc__ "" "t.__sizeof__ ()--size of T in memory, in bytes" "" Pass

6. Dictionary (unordered)To create a dictionary:

123	person  =  < Code class= "python plain" >{ :  "mr.wu" ,  ' age ' :  18 or person  =  dict "mr.wu" ,  :  18

Common Operations:

• Index
• New
• Delete
• key, value, Key-value Pairs
• Cycle
• Length

DictPS: loops, Range,continue and break other 1. For loopThe user iterates through the contents of an object in order, ps:break, continue

123	li =[11,22,33,44]for item in li:    printitem

2, enumrateAdd an ordinal to an object that can be iterated

123	li =[11,22,33]for k,v inenumerate(li, 1):    print(k,v)

3. Range and xrangeSpecify a range to generate the specified number

12345678

printrange(1, 10)# 结果：[1, 2, 3, 4, 5, 6, 7, 8, 9]printrange(1, 10, 2)# 结果：[1, 3, 5, 7, 9]printrange(30, 0, -2)# 结果：[30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2]

Exercises

first, the element classification

There is a collection of the following values [11,22,33,44,55,66,77,88,99,90 ...], saving all values greater than 66 to the first key in the dictionary, and saving the value less than 66 to the value of the second key.
That is: {' K1 ': All values greater than 66, ' K2 ': all values less than 66}

second, FindFinds the elements in the list, removes the spaces for each element, and finds all elements that begin with a or a and end with C. Li = ["alec", "aric", "alex", "tony", "rain"] tu = ("alec", "aric", "alex", "Tony", "rain") dic = {' K1 ': "alex", ' K2 ': ' Aric ', ' K3 ': ' Alex ', ' K4 ': ' Tony '} third, The output commodity list, the user enters the serial number, displays the user to select the productProduct Li = ["mobile phone", "computer", "mouse pad", ' yacht ') four, Shopping Cart

Functional Requirements:

• Require users to enter total assets, for Example: 2000
• Display the list of items, let the user select the item according to the serial number, add the shopping cart
• purchase, if the total amount of goods is greater than the total assets, indicating that the account balance is insufficient, otherwise, the purchase succeeds.
• Add: can recharge, a product to remove the shopping cart

123456

goods =[    {"name": "电脑", "price": 1999},    {"name": "鼠标", "price": 10},    {"name": "游艇", "price": 20},    {"name": "美女", "price": 998},]

V. User interaction, showing the choice of three-level linkage between provincial and municipal counties

12345678910111213

dic ={    "河北": {        "石家庄": ["鹿泉", "藁城", "元氏"],        "邯郸": ["永年", "涉县", "磁县"],    }    "河南": {        ...    }    "山西": {        ...    }}

Python development "full stack-day-iv": python basic data type