2. File operation - write

1、 Pattern mode=w

#  Pattern mode=w  Write data to file , If the file does not exist, create a new file , If the file exists , Then empty the file and write again 
f = open(' New files .txt',mode='w',encoding='utf-8')
f.write(' the weather is nice today ')

2、 Write the data in the list to the text

Be careful ：1. normal open Outside the loop ,

2. The list is connected after being written to the file , It needs to be separated by carriage return

#  A list is written to the file 
l = ['python','java','go']
f = open(' New files .txt',mode='w',encoding='utf-8')
for i in l:
    f.write(i)
    f.write('\n')

3. Append write (append)：a

l = ['python','java','go']
f = open(' New files .txt',mode='a',encoding='utf-8')
for i in l:
    f.write(i)

4. File opening and playing need to be closed ：f.close(), Not closing , When the file is large, it will consume server resources , File operation occupied , You need to wait until the program finishes running before releasing resources