File Write and Read

In this module,  a simple simple three (3) field data base stored as a comma delimited text file will be created by one program and then read by the second program.

Writing to a file

#Text File write written in Python

print 'Write to a text file' #program heading

#main program

#create and open file for writing

f=open('friend.txt', 'w')

#get data

given = raw_input("Enter given name -> ")

surname = raw_input("Enter surname -> ")

age = raw_input("Enter age -> ")

onelineoftext = given + ',' + surname + ','+ age + '\n'

#write data to file

f.write(onelineoftext)

#add more data??

more = raw_input("Enter Y to add more or N to finish -> ")

while more == 'Y':

    given = raw_input("Enter given name -> ")

    surname = raw_input("Enter surname -> ")

    age = raw_input("Enter age -> ")

    onelineoftext = given + ',' + surname + ','+ age + '\n'

    f.write(onelineoftext)

    more = raw_input("Enter Y to add more -> ")

#close the file

f.close() 

Note:

 /n adds a newline sequence to the end of the line

Reading from a file

#Text File read written in Python

print 'Read from a text file' #program heading

#main program

#open the file for reading

f=open('friend.txt', 'r')

#read a line of text from file 

onelineoftext = f.readline()

while onelineoftext != '':

    print onelineoftext

    onelineoftext = f.readline()

#close the file

f.close()

Note:

• The "w" parameter in the open function allows you to create and write to a file.  
• The "a" parameter in the open function allows you to append to a file.
• The "r" parameter in the open function allows you to read from a file.

Exercises

1. Create a simple database management system by combining the two programs above into procedures. Then use an array to store your data while in memory. Create a simple sort function that will sort your data into age order.
2. ex2
3. ex3

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