[Python study notes] Coursera's PY4E study notes - File

1. Open the file

Open the file with handle=open(filename,mode). This function will return a handle (should be translated as "handle") to manipulate the file, the parameter filename is a string. The parameter mode is optional, 'r' stands for read file, 'w' stands for write file.

example:

>>> fhand=open('mbox.txt','r')
>>> print(fhand)
<_io.TextIOWrapper name='mbox.txt' mode='r' encoding='UTF-8'>

 The file handle can be regarded as a sequence of strings, and each line of the file example is the content of this sequence of strings.

Example: Counting the number of lines in the file content

fhand=open('mbox.txt')
count=0
for line in fhand:
    count=count+1
print('Line Count:',count)

$ python open.py
Line Count:132045

Example: Retrieving file content

fhand = open(;mbox-short.txt')
for line in fhand:
    if line.startswith('From:'):
        print(line)

 

2. Read the file

Use read() to read the entire file (including newlines, etc.) into a single string.

example:

>>> fhand=open('mbox-short.txt')
>>> inp=fhand.read()
>>> print(len(inp))
94626
>>> print(inp[:20])
From stephen.marquar