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CBSE Class 12 Computer Science Question 138 of 145

File Handling — Question 18

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Question

Question 18

Write a function to search and display details of all trains, whose destination is "Delhi" from a binary file "TRAIN.DAT". Assuming the binary file is containing the objects of the following dictionary type:

Train = {'Tno': ..............., 'From': ...............,'To': ...............}
Answer

Let the dictionary contained in file "TRAIN.DAT" be as shown below:

Train1 = {'Tno': '1234', 'From': 'Mumbai', 'To': 'Delhi'}
Train2 = {'Tno': '5678', 'From': 'Chennai', 'To': 'Delhi'}
Train3 = {'Tno': '9012', 'From': 'Kolkata', 'To': 'Mumbai'}
Train4 = {'Tno': '3456', 'From': 'Delhi', 'To': 'Bangalore'}
Train5 = {'Tno': '7890', 'From': 'Pune', 'To': 'Delhi'}

import pickle

def search_trains():
    found = False

    try:
        file = open("TRAIN.DAT", "rb")

        while True:
            trains = pickle.load(file)
            if trains['To'] == "Delhi":
                print("Train no: ", trains['Tno'])
                print("From: ", trains['From'])
                print("To: ", trains['To'])
                found = True
                
    except EOFError:
        if found == False:
            print("End of file reached. No such records found.")
        else:
            print("Search Successful")
        file.close()

search_trains()
Output
Train no:  1234
From:  Mumbai
To:  Delhi
Train no:  5678
From:  Chennai
To:  Delhi
Train no:  7890
From:  Pune
To:  Delhi
Search Successful