Hello Folks....!!!
Today we are going to see how to read a file in python.
read( ) method in Python
The file must be first opened in read mode. To know how to open a file in
read mode, refer this link. read() is a built-in method
in python, which provides facilities to read either specified number of
bytes or up to the end of the file. The syntax is as follows:
file_object.read(size)
Here if the size is mentioned, it reads the specified number of bytes,
otherwise the whole file is read. Let us look at an example.
Let us consider a text file sample_file.txt. It has few lines on Python. I have given the snap shot of the file I
used below.
Now let us open and read its contents into a string data structure. You can
read it into any data structure of your choice. Let us read first ten bytes.
So we pass the parameter 10.
Note that a blank space will also be considered as a byte, To explain the
output got I am denoting the spaces with an underscore (_). The output is
Python_is_. If you count with the underscores, then you will get 10 bytes
long string. If you don't pass any parameter for the method and simply
write f.read(), the you will get the
output below.
Now if you use read (10), the first 10 bytes will be rad and the file
pointer will be placed after the 10th byte. Now if use an another read (10),
before closing the file, then you will get next 10 bytes. For example look
at the code below.
tell() and seek() operations
If you want to know where the cursor (file pointer) is currently placed you
can use file_object.tell(). It will
return at what number of byte the cursor is. To reposition the cursor, you
can usefile_object.seek(byte_number). This will place the cursor in the specified byte number. Let us look at
an example.
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