Python Programming for Biology: Bioinformatics and Beyond

Method

Description

f.close()

Closes a file object so that it is no longer used for reading

or writing. This often happens implicitly when the handle

on the object falls out of scope (e.g. returning from a

function).

f.flush()

Flushes out and writes any cached file data (held in the

file buffer). Note use of os.fsync(fileObj.fileno()) may

additionally be required to force the operating system to

write immediately.

f.fileno()

Gives a number that identifies the particular file object to

low-level operating-system procedures.

f.read(size)

Reads a specified number of bytes from a file object as a

string or (from Python 3) as bytes if in binary mode,

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although this may be limited by the end of the file. With

no size argument reads all data from the file.

f.readline(size)

Reads a single line from file, optionally specifying the

maximum

number of bytes to read (thus potentially truncating the

line).

f.readlines(targetSize)

Reads all the lines from a file object. With optional

argument, no more lines are read once total size of lines

read so far exceeds the given number of bytes.

f.seek(offset, code)

Moves the file object’s current read/write position to a

given byte position. Generally more useful for ‘binary’

files than text files. Optional second argument is 0, 1 or 2

to seek relative to the start (default), current position or

file end respectively.

f.tell()

Retrieves the file’s current read/write position.

f.truncate(size)

Truncates the file to the current read/write position, or to

an optionally specified size.

f.write(text)

Writes a specified text string or bytes (if Python 3 binary

mode) to file. Note that the data may not actually be

written to disk until the buffering cache is full.

f.writelines(texts)

Writes an ordered collection of text strings or bytes (if

Python 3 binary mode) to file.