Question

IN PYTHON

1. Write the script test3.py that creates and populates a list of OnlineStudent objects. It inputs a requested student, then prints the fields for that student, and also the username of each student in the student's study group. See the pseudocode in Item 3 below.
2. Use the new type of for loop that you can use for reading from a file:

   # Instead of writing a loop like this
   fin = open("input-file", "r")
   line = fin.readline( )
   while line != "":
       process line
       line = fin.readline( )
   fin.close( )
   
   # write it like this:
   fin = open("input-file", "r")
   for line in fin:
       process line
   fin.close( )
   

3. Pseudocode for test3.py:

   Initialize list to hold OnlineStudent objects, call it students.
   Open input file students.txt.
   For all lines in the input file
       Use split to extract the fields list.
       Assign variable names to fields.
       Create OnlineStudent object.
       Append object to list.
   End for.
   Close input file object.
   
   Sort array by username.
   
   Print list of OnlineStudent objects.
   
   Open input file study-groups.txt.
   For all lines in input file
       Use split to extract the fields list.
       For each student s in students list
           If s.username is equal to fields[0]
               For the index i in the range 
                   from 1 to length of fields list - 1
   
                   Append fields[i] to s.study_group list.
               End for.
           End if.
       End for.
   End for.
   
   For s in students' list
       Print s.
       Print usernames of study group members.
   End for. 
   
   Input requested username.
   for each student s in students list
      If requested username is equal to s.username
          Print s.
          For t in s.study_group
              Print t    
          End for.
   
   Close input file.               
   

4. Challenge Problem: Instead of printing the usernames of the students in the study group, print the first names of the students in the study group.

Answer 1

programming language: python

As myself defined some attributes as fields in the OnlineStudent Class. You can change as you wish.

Save the files in appropriate location.

source code:

class OnlineStudent:
study_group=[]
def __init__(self,username,first_name,last_name,subject,age):
#u can change as u want
self.username=username
self.first_name=first_name
self.last_name=last_name
self.age=age
self.subject=subject
student=[] #student array object
fin = open("students.txt", "r")
for line in fin:
detail=line.split() # name given just for understanding
student.append(OnlineStudent(detail[0],detail[1],detail[2],detail[3],detail[4]))#data will change depends the number #of fields in input file
fin.close()
def keyname(data): # for sorting with username
return data[0]
student.sort(key = keyname)
#printing the data from student list
for data in student:
print(data)
#Opening study_group file and working on it.
fin = open("study-groups.txt", "r")
for line in fin:
fields=line.split()
for s in student:
if s.username==fields[0]:
k=[]
for i in range(1,len(fields)):
k.append(fields[i])
s.study_group.append(k)
fin.close()
for s in student :
print (s)
if s.study_group :
print(s.first_name)#prints the first name of the study group
usrname=input("Enter the username : ")
for s in student:
if usrname==s.username:
print(s)
for t in s.study_group:
print(t)