Zybooks Chapter 12 Files Participation Activity Questions

myscript.py infile.txt out

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 ____________________________________________

b'\x05\x15\xf2'

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

b'\x1a'

Assign x with a bytes object with a single byte whose hexadecimal value is 0x1a. Use a bytes literal. x = ____________________________________________

csv.reader(myfile)

The file "myfile.csv" contains the following contents: Airline,Destination,Departure time,Plane Southwest,Phoenix,615,B747 Alitalia,Milan,1545,B757 British Airways,London,1230,A380 Complete the statement to create a csv module reader object to read myfile.csv. import csv with open('myfile.csv', 'r') as myfile: csv_reader = ____________________________________________

True

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

True

The statement f.write(10.0) always produces an error . True False

False

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

False

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

The size in bytes of the file at path_str.

What does os.path.getsize(path_str) return? The length of the path_str string. The combined size of all files in path_str directory. The size in bytes of the file at path_str.

False

What does the callos.path.isfile('C:\\Program Files\\')return? True False

"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"

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

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

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

True

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

'>I', my_bytes

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

lines[1]

Complete the program by echoing the second line of "readme.txt" my_file = open('readme.txt') lines = my_file.readlines() print(_____________________________________________ ) #....

row[1]

Complete the statement so 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(____________________________________________)

open('readme.txt')

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

'>h', my_num

Complete the statement to pack an integer variable "my_num" into a 2-byte sequence. Assign my_bytes with the sequence. Use the byte ordering given by ">". my_bytes = struct.pack(____________________________________________)

my_file.read(500)

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

a

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

a+

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

'subdir', 'output.txt'

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

data.txt

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

w

If the file exists, existing contents will be overwritten by new data. If not, data will be written to a new file. f = open('myfile.txt', '_____________________________________________')

'rb'

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

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

Open "myfile.txt" as read-only in binary mode. f = ____________________________________________