COSC 1306 - SET 4: Files

The write() method immediately writes data to a file.

False

Use of a with statement is not recommended most of the time when opening files.

False

What does the call os.path.isfile('C:\\Program Files\\') return?

False

Assign x to a bytes object containing three bytes with hexadecimal values 0x05, 0x15, and 0xf2. Use a bytes literal x = -- blank --

b'\x05\x15\xf2'

Assign x to a bytes object with a single byte whose hexadecimal value is 0x1a. use a bytes literal. x = -- blank --

b'\x1a'

Complete the program by echoing the second line of 'readme.txt' my_file = open('readme.txt') lines = my_files.readlines() print( -- blank -- )

lines[1]

Complete the statement to read up to 500 bytes from "readme.txt" into the contents variable my_file = open('readme.txt') contents = --blank--

my_file.read(500)

A script 'myscript.py' has two command line arguments, one for an input file and a second for an output file. Type a command to run the program with input file 'infile.txt' and output file 'out' > python

myscript.py infile.txt out

Open 'myfile.txt as read-only in binary mode. f = --blank --

open('myfile.txt', 'rb')

Complete the statement to open the file "readme.txt" for reading. my_file = --blank--

open('readme.txt')

Complete the statement such that the program prints the destination of each flight in myfile.csv import csv with open('myfile.csv', 'r') as myfile: csv_reader = csv.reader(myfile) for row in csv_reader: print( -- blank -- )

row[1]

Assume that variable my_bytes is b'\x00\x04\xff\x00' Complete the statement to assign my_num to the 4-byte integer obtained by unpaking my_bytes. Use the byte ordering given by '>' my_num = struct.unpack( -- blank -- )

'>I', my_bytes

Complete the statement to pack an integer variable 'my_num' into a 2-byte sequence assigned to my_bytes. use the byte ordering given by '>' my_bytes = struct.pack( -- blank -- )

'>h', my_num

Data will be appended to the end of existing contents. f = open('myfile.txt', --blank-- )

'a'

Existing contents will be read, and new data will be appended. f = open('myfile.txt', --blank-- )

'a+'

Open 'data.txt' as read-only in binary mode f = open('data.txt', -- blank -- )

'rb'

What is returned by os.path.joinn('sounds', 'cars', 'honk.mp3') on Mac OS X? Use quotes in the answer

'sounds/cars/honk.mp3'

What is returned by os.path.join('sounds', 'cars', 'honk.mp3') on Windows? Use quotes in the answer

'sounds\\cars\\honk.mp3'

Fill in the arguments to os.path.join to assign file_path as 'subdir\\output.txt' (on Windows) file_path = os.path.join( -- blank -- )

'subdir', 'output.txt'

Data will be written to a new file. f = open('myfile.txt', --blank-- )

'w'

What is the output of the following program? import os p = 'C:\\Programs\\Microsoft\\msword.exe' print(os.path.split(p))

('C:\\Programs\\Microsoft', 'msword.exe')

What does os.path.getsize(path_str) return?

The size in bytes of the file at path_str.

The flush() method (and perhaps os.fsync() as well) forces the output buffer to write to disk.

True

The statement f.write(10.0) always produces and error

True

When using a with statement to open a file, the file is automatically closed when the statements in the block finish executing.

True

Complete the statement to create a csv module reader object to read mtfile.csv import csv with open('myfile.csv', 'r') as myfile: csv_reader = --blank--

csv.reader(myfile)

For a program run as 'python scriptname data.txt', what is sys.argv[1]? Do not use quotes in the answer

data.txt