13 days python learning Notes

Exchanging data between different platforms 1, the frame, the language

Since .txt files do not have the semantic tags, not suitable for the format of data exchanged between different platforms, frames and languages.

Different platforms, the exchange of data between frame formats and languages: CSV, TSV, json etc.

2 CSV file

Read and write 2.1 CSV files do not need to download additional libraries, the system comes

2.2 to read data

Import module

import csv

Read data

with open(‘C:\\data.csv’,encoding=’utf8’) as f:

    reader=csv.reader(f)

NOTE: After reading the file, using the next () method reads the first column, and then use the cycle in which data is read

v_lietou=next(reader)

NOTE: use namedtuple column head and the corresponding values:

ROW=namedtuple(‘ROW’,v_lietou)

Then for any one line:

line=ROW(*line)

Note: CSV file directly supports reading way dictionary table:

with open(‘C:\\data.csv’,encoding=’utf8’) as f:

    reader=csv.DictReader(f)

2.3 write data

Import module

import csv

data input

headers=[‘name’,’dep’,’sal’]

val=[(‘tom’,’dev’,600),(‘peter’,’pro’,300),(‘jim’,’che’,500)]

with open(‘C:\\data.csv’,’w’,encoding=’utf8’) as f:

    writer=csv.writer(f)

    writer.writerow(headers)

    writer.writerows(val)

Note: write a single line is writerow, write multiple lines are writerows

Note: CSV files can also support writing dictionary tables

with open(‘C:\\data.csv’,’w’,encoding=’utf8’) as f:

    writer=csv.DictWriter(f,headers)

    writer.writeheader()

    writer.writerows(val)

3 json file

json format similar table and dictionary

json is True, False, Null are lowercase

3.1 json string read

Import module

Import JSON 

Data = { ' name ' : ' Tom ' , ' DEP ' : ' dev ' , ' SAL ' : 6000}

　　Dictionary converted into json format

= json_data json.dumps (Data) 

    converted into a dictionary format json 

DATAl = json.loads (json_data)

3.2 json file to read and write

Write the file: json.dump (data, file name)

with open('data.json','w',encoding='utf-8') as f:

    json.dump(data,f)

Read the file: json.load (filename)

with open('data.json','r',encoding='utf-8') as f:

    data=json.load(f)

    print(data)

4 excel file read

Read and write Excel files without their own library, you need to install xlrd

The main methods are:

Open File: book = xlrd.open_workbook (file)

Acquire table: sheet = book.sheet_by_index (0) or book.sheet_by_name (name)

Get the number of rows in the table: num_row = sheet.nrows

Obtaining i-th row data: data = sheet.row_values (i)

13 days python learning Notes

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