Python data type (ii)

• List of Python data types

  A list is a collection of data defended in square brackets "[]", with different members separated by ",". The list can contain any data type, or it can contain other lists, which can be accessed by the list by ordinal. You can sort, add, delete, and so on in a script, and you can change the value of any member in the list.

  • Common list Operations

List operations	Describe
List.append	Append member
List.count (x)	Count the number of occurrences of the parameter X in the list
List.extend (L)	Append another list to the list L
List.index (x)	Get the position of the parameter X in the list
List.insert ()	Inserting data into the list
List.pop ()	Deletes the last value in the list and returns the deleted value
List.remove ()	Remove a member from a list
List.reverse ()	Reverses the order of the members in the list
List.sort ()	Sort members in a list

• Python Data type: Dictionary

A dictionary is a special kind of data type in Python and is a collection of data that encloses {} with braces. The biggest difference between a dictionary and a list is that the dictionary is unordered, and the members are accessed through keys in the dictionary.

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Usually the operation of a dictionary

Dictionary operations	Describe
Dic.clear ()	Empty dictionary
Dic.copy	Copy Dictionary
Dic.get (k)	Get the value of the key K
Dic.has_key (k)	Whether to include the key K
Dic.items ()	Get a list of keys and values
Dic.keys ()	Get a list of keys
Dic.pop (k)	Delete key k
Dic.update ()	With new members
Dic.values ()	Get a list of worthwhile

Python data type: A file file can also be considered a data type in Python, and a file object is returned when a file is opened with Python's built-in function open

Open (filename,mode,bufsize) fiename the file to be opened mode optional, file Open, R, read-only w overwrite write a append bufsize optional parameter, buffer size E G:user_file=open ("User.log", "R") print (user_file) E:\Python34\python.exe e:/one/day1/day1homework1.py<_io. Textiowrapper name= ' user.log ' mode= ' r ' encoding= ' cp936 ' >process finished with exit code 0

• Basic operation of the file

  
  

  File operations	Describe
  File.read ()	Reads the entire file into a string
  File.readline ()	Read a line of a file into a string
  File.readlines ()	Read the entire file into the list by line
  File.write ()	Writing a string to a file
  File.writelines ()	Write a list to a file
  File.close ()	Close an open file

  
  

  • File.read

User_file=open ("User.log", "R") User_line=user_file.read () print (user_line) E:\Python34\python.exe e:/one/day1/ Day1homework1.pyduqiu,123wangming,123

• File.readline

User_file=open ("User.log", "R") User_line=user_file.readline () print (user_line) E:\Python34\python.exe e:/one/day1/ Day1homework1.pyduqiu,123process finished with exit code 0

• File.readlines

User_file=open ("User.log", "R") User_line=user_file.readlines () print (user_line) E:\Python34\python.exe e:/one/day1 /day1homework1.py[' duqiu,123\n ', ' wangming,123 ']process finished with exit code 0

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Python data type (ii)