Data analysis

First step ： Collect data （ Data sources ： Reptiles （ Network data sources ）、 Questionnaire collection 、 Buy data from specialized companies 、 The database established by the company ）
The second step ： Data preprocessing （ Tools ：python、excel、 Use both hands ）
The third step ： With the aid of algorithms 、 Model, etc
cost reduction , Increase revenue

File operations

Data persistence ： Data changes from transient state to persistent state
open( Parameters 1、 Parameters 2、 Parameters 3…) — Open file , Open a file object

• Parameters 1： Path and filename

• Parameters 2： The way the file is opened ( Read and write )

• Parameters 3： The encoding form of file opening ：utf-8

Parameters 1

• grammar ： '.‘ Represents the current folder （ You can omit it ）;’…' To return to the next level

• Between folders and between folders and files ’/' interval
  Path can be divided into relative path and absolute path

• Relative paths ： Based on the current reference , Another file corresponds to the location of the reference , You should use ’/’

• Absolute path ： Take the disk as a reference , Use ’’
  Suppose you are currently in a folder B in , If you want to find a file A： …/ Folder A/ file A

open('./test/ file 1')

Parameters 2：

r a w +

• r: read-only , If the file doesn't exist 、 Report errors

• w: Just write , file does not exist , First automatically create ; If the file exists , Empty first （ If a folder does not exist , Don't create a folder ）

• a: Just write , file does not exist , Report errors ; If the file exists , Additional

• +: Can read but write , take r、a、w Become readable and writable symbols ：r+、a+、w+;python Operation file , Read or write , You cannot read and write at the same time
  r、w、a、+ —> File editing method
  t、b ----> Document presentation form
  t： Text
  b： byte
  r、w、a Equivalent to rt、wt、at -rb、wb、ab、br、bw、ba Represents the operation of a file in bytes

Parameters 3

encoding = ‘utf-8’

f = open(r'./test/ file 1', 'r', encoding='utf-8')print(f)

read() Read information from file objects

result = f.read()print(result, type(result))

notes ： All files are stored in binary in memory

f1 = open(r'./test/123.jpg', 'rb')result1 = f1.read()print(result1, type(result1))

File write operation

• newly build xxx Name file

• Write content

• Keep close

• Write operations

f = open('./test/ Geese .txt', 'w', encoding='utf-8')str_1 = '\t Chant goose \n\t lo bingwang \n Goose, goose and goose , Song item to the sky .\n White hair dew , Red palm dials clear waves .'print(str_1)f.write(str_1)f.write('\n Chant goose ')f.close()# f.write('1')# ValueError: I/O operation on closed file.# I/O--Input/Out

File read operation

f = open('./test/ Geese .txt', 'r', encoding='utf-8')

read(): Read everything at once , The read result is a string

print(f.read())

readline()： Read one line at a time , The read result is a string

print(f.readline())

readlines(): Read all at once , Each line is treated as an element in the list

print(f.readlines())f.close()

notes ：
seek()— The pointer ： During file operation, the pointer is at the beginning of the file by default , The pointer changes as the file is manipulated .

Picture reading and writing operation

Read the picture

f1 = open('./test/ Administrators .jpeg', 'rb')result = f1.read()print(result)f1.close()

Download the pictures

f2 = open('./test/photo1.jpeg', 'wb')f2.write(result)f2.close()

author ： Have a strong sense of self-management .

Game programming , A game development favorite ~

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