[Python知识库]3.15 haas506开发教程-example-文本操作

1.文本读取/写入

• main.py

# coding=utf-8

# @file         main.py
# @author       wyk
# @version      V01
# @date         2021.11.4
# @brief        main code 0f sd_read_write
# /sdcard0/filename1.txt

'''
1表示 可以，0表示不行
_____________________________________________
模式      r     r+      w      w+     a    a+
读        1     1       0      1      0    1
写        0     1       1      1      1    1
创建      0     0       1      1      1    1
覆盖      0     0       1      1      0    0
指针在头  1     1       1      1      0    0
指针在尾  0     0       0      0      1    1 
_____________________________________________
'''
import uos

def main():
    #启用sd卡
    uos.mountsd()
    #查看sd卡中有什么文件
    print("files in sd card  are:",uos.listdir('/sdcard0'))
    read_from_txt()
    print('-'*30)
    write_to_txt()


def read_from_txt():
    #sd卡中已经有filename1.txt，读取他的内容
    print('read_from_txt test')
    f=open('/sdcard0/filename1.txt','r')
    #读取指定一行的内容
    content1=f.readline()
    print('content :',content1)
    f.close()


def write_to_txt():
    #1.将内容写入txt文件中（当sd卡中没有filename2.txt时，w模式会创建该文件）
    #2.然后再读取txt文件内容
    print('write_to_txt test')
    f=open('/sdcard0/filename2.txt','w')
    lens=f.write("type anything you want")
    #显示写入文件的字符数
    print("lens of content:",lens)
    f.close()

    print('-'*30)
    p=open('/sdcard0/filename2.txt','r')
    c=p.read(100)
    print('content in filename2.txt is:',c)
    p.close()



if __name__ == '__main__': 
    main()

• 结果

files in sd card  are: ['record1.pcm', 'System Volume Information', 'haas506.mp3', 'helloworld.mp3', 'filename1.txt', 'filename2.txt']
read_from_txt test
content : welcome come to use haas 506
------------------------------
write_to_txt test
lens of content: 22
------------------------------
content in filename2.txt is: type anything you want