Python Learning Day6

Yesterday review

Dict:dic = {'name':'Alex'} added: dic[' Age'] = 21presence on overwrite Dic.setdefault () does not increase Delete: Pop () is deleted by key, with return value cleardeldic['name'] Popitem () random delete returned is Ganso update Dic.keys () dic.values () Dic.items () forKvinchDic.items ():Print(k,v) dic.get (key,none)

Coding issues

ASCII A:000000108-bit one-byte Unicode a:00000000 00000001 00000010 0000010032 bits in four bytes:00000000 00000001 00000010 0000011032-bit four-byte UTF-8 a:001000008 bits in one byte:00000001 00000010 0000011024-bit three-byte GBK A:000001108 bits in one byte:00000010 0000011016 bits Two bytes1, the binary between each encoding, is not mutually recognized, will produce garbled. 2, file storage, transmission, cannot be Unicode (only utf-8 utf-16gbk,gb2312,asciid, etc.) PY3:STR is encoded in memory in Unicode. Bytes type for English: str: Presentation form: S='Alex'Encoding Method:010101010Unicode Bytes: representation: S= b'Alex'Encoding Method:000101010 Utf-8GBK .... For Chinese: str: Expressive form: s='China'Encoding Method:010101010Unicode Bytes: representation: S= b'x\e91\e91\e01\e21\e31\e32'Encoding Method:000101010 Utf-8 GBK

Summary of small knowledge points

= Assignment = = Comparison value is equal isCompare, the memory address ID (content) is compared#li1 = [A]#Li2 = Li1#Li3 = Li2#Print (ID (LI1), ID (li2))#Numeric, string small data pool#range of Numbers-5--#string: 1, cannot have special characters#2,s*20 is still the same address, and S*21 is two addresses later.#I1 = 6#i2 = 6#Print (ID (i1), ID (i2))#I1 =#i2 =#Print (ID (i1), ID (i2))#The remaining list dict tuple set#L1 = [1,]#L2 = [1,]#print (L1 is L2)#s = ' Alex '#S1 = B ' Alex '#Print (S,type (s))#Print (S1,type (S1))#s = ' China '#Print (S,type (s))#S1 = B ' China '#Print (S1,type (S1))S1='Alex'#encode encoding, how to put str---Bytes, ()S11 = S1.encode ('Utf-8') S11= S1.encode ('GBK')Print(S11) S2='China'S22= S2.encode ('Utf-8') S22= S2.encode ('GBK')Print(S22)

Python Learning Day6