Detailed explanation of using Python file operation open to read and write files to append text content examples

1.open After using open to open a file, you must remember to call the close() method of the file object. For example, you can use the try/finally statement to ensure that the file can be closed finally.

file_object = open('thefile.txt')
try:
 all_the_text = file_object.read( )
finally:
 file_object.close( )

Note: The open statement cannot be placed in the try block, because when an exception occurs when opening the file, the file object file_object cannot execute the close() method.
2. Read files, read text files input = open('data', 'r')

#第二个参数默认为r
input = open('data')

Read binary files input = open('data', 'rb')
Read all contents file_object = open('thefile.txt')

try:
 all_the_text = file_object.read( )
finally:
 file_object.close( )

Read fixed bytes file_object = open('abinfile', 'rb')

try:
 while True:
 chunk = file_object.read(100)
 if not chunk:
 break
 do_something_with(chunk)
finally:
 file_object.close( )

Read each line list_of_all_the_lines = file_object.readlines( )
If the file is a text file, you can also directly traverse the file object to get each line:

for line in file_object:
 process line

3. Write file Write text file output = open( 'data.txt', 'w')
Write binary file output = open('data.txt', 'wb')
Append write file output = open('data.txt', 'a')

output .write("\n都有是好人")
output .close( )

Write data file_object = open('thefile.txt', 'w')

file_object.write(all_the_text)
file_object.close( )

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