Question

Define a function readList with one parameter, the (string) name of a file to be read from. The file consists of integers, one per line. The function should return a list of the integers in the file.

Answer 1

Answer:

Here is the Python function readList:

def readList(filename):  #function definition of readList that takes a filename as a parameter and returns a list of integers in the file

   list = []  # declares an empty list

   with open(filename, 'r') as infile:  # opens the file in read mode by an object infile

       lines = infile.readlines()  # returns a list with each line in file as a list item

       for line in lines:   #loops through the list of each line

           i = line[:-1]  # removes new line break which is the last character of the list of line

           list.append(i)  # add each list item i.e. integers in the list

       return list  #returns the list of integers

#in order to check the working of the above function use the following function call and print statement to print the result on output screen

print(readList("file.txt")) #calls readList function by passing a file name to it

Explanation:

The program is well explained in the comments mentioned with each line of the code.

The program declares an empty list.

Then it opens the input file in read mode using the object infile.

Next it uses readLines method which returns a list with each line of the file as a list item.

Next the for loop iterates through each item of the file which is basically integer one per line

It adds each item of list i.e. each integers in a line to a list using append() method.

Then the function returns the list which is the list of integers in the file.

The program along with it output is attached. The file "file.txt" contains integers 1 to 8 one per line.