Python lesson two, operators and basic data types

the python operator 1. Arithmetic operation:

2. Comparison operation:

3. Assignment Operation:

4. Logical Operation:

5. Member Arithmetic:

Basic data types for Python 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 -9223372036854775808~9223372036854775807 2. Boolean valueTrue or False 1 or 0 3. String

"Hello World"

String Common functions:

• Remove blank strip (self, Chars=none)
• Split Partition (self, SEP)
• Length __len__ (self)
• Index []
• Slice [:]

4. ListTo create a list:

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

Basic operation:

• Index []
• Slice [:]
• Append Append (self, p_object)
• Delete Remove (self, value)
• Length Len
• Loop for
• Contains

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 [:]
• Loop for
• Length Len
• Contains

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 [key]
• Added [Key1]=value
• Delete Clear
• Key, value, key-value pair Keys,values,viewitems
• Loop default Loop key
• Length Len

PS: 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]

Python lesson two, operators and basic data types