Chapter 8

Question 1

What is a more convenient function when we cannot use input() function to read large amounts of data?

Answer 1

We prepare the needed information as an external file and get our program to read the data in that external file.

Question 2

What is the first step in making your program read an external file?

Answer 2

We create a .txt file with the text which we want our program to read and save it on desktop or a preferred location.

Question 3

What’s the second step?

Answer 3

We write the below script and save it as .py file in the same folder as .txt

Question 4

What does the first line in the program do?

f=open(‘myfile.txt’,’r’)

Answer 4

It opens the .txt file and reads it. r= read mode
open() function open the .txt file
the two arguments entail the path of the file and the mode

Question 5

How would the first argument look like if the .txt and .py file weren’t saved in the same folder but a different folder in the C drive

Answer 5

Then the first argument would have been

‘C:\PythonFiles\myfile.txt’ (with double backslash \).

Question 6

What is ‘w’ mode?

Answer 6

for writing only

Question 7

What is ‘a’ mode?

Answer 7

for appending

Question 8

What is ‘r+’ mode?

Answer 8

for both reading + writing

Question 9

What does the next statement do?

firstline = f.readline()

Answer 9

It reads the first line in the .txt file and assigns it to the variable firstline

Question 10

Each time the readline() function is called, it _______. In our program, readline() was called twice. Hence the______ will be read.

Answer 10

reads a new line from the file. first two lines

Question 11

How would you tweak the code if you do not want the extra line between each line of the text?

Answer 11

print(firstline,end=’’)

its two single quotes

Question 12

Why is it important to close the file?

Answer 12

to free up system resources

Question 13

Write an example script for using the For loop for reading the text from the .txt file

Answer 13

Find the example attached with results

Question 14

What mode will you use to write to a text file?

Answer 14

‘a’ append mode

Question 15

Can we use the ‘w’ mode ?

Answer 15

we can. However, it will erase all the previous content in the file if it already exists

Question 16

Write a script for adding the below to myfile.txt
This sentence will be appended
Python is Fun

Answer 16

Each time the attached script is run, it will add
This sentence will be appended.
Python is Fun!
to myfile.txt

Question 17

How does the usage of ‘\n’ helps?

Answer 17

It adds the sentences on a new line

Question 18

Why do we want to read a file by buffer size?

Answer 18

So that our program does not use too much memory resources

Question 19

How can we open and read text files by buffer size?

Answer 19

By using the read() function.

This function allows us to use the buffer size we want

Question 20

Write a script for opening and reading text files by buffer size

Answer 20

Question 21

What do the first two lines of the code listed below do?

inputFile.txt and outputFile.txt

Answer 21

It opens two files for reading and writing respectively

Question 22

What does the statement

msg=inputFile.read(10) do?

Answer 22

The value 10 in the parentheses tells the read function to only read 10 bytes at a time

Question 23

What does the while len(msg) do?

Answer 23

It checks the length of the variable msg. This means that as long as the length is not zero, the while loop will continue to run.

Question 24

Within the while loop, the statement outputFile.write(msg) _________

Answer 24

writes the message to the output file

Question 25

After writing the message, the statement msg = inputFile.read(10)?

Answer 25

reads the next 10 bytes and keeps doing it until the file is read

Question 26

To prove that only 10 bytes is read at a time, you can change the line outputFile.write(msg) in the program to ___________?

Answer 26

outputFile.write(msg+’\n’)

Question 27

What are binary files?

Answer 27

Files that contain non-text, such as image or video files

Question 28

What modes do we use for working with binary files?

Answer 28

‘rb’ or ‘wb’ mode

Question 29

Write a script for opening, reading and reproducing an image file

Answer 29

Question 30

What will the script for myimage 1 do?

Answer 30

reproduce an additional image on the desktop looking exactly like myimage.jpg

Question 31

The remove() function_______

Answer 31

deletes a file

Question 32

What is the syntax for removing a file

Answer 32

remove(‘myfile.txt’)

Question 33

The rename() function________

Answer 33

renames a file

Question 34

What is the syntax for rename function?

Answer 34

rename(‘oldfile.txt’,’newfile.txt’)