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File Handling Ocr

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Exam code:J277

File Handling

What is file handling?

File handling is the use of programming techniques to work with information stored in text files
Examples of file handing techniques are:
- opening text files
- reading text files
- writing text files
- closing text files

Concept	OCR exam reference	Python
Open	`file = open("fruit.txt")`	`file = open("fruit.txt","r")`
Close	`file.close()`	`file.close()`
Read line	`file.readline()`	`file.readline()`
Write line	`file.writeline("Oranges")`	`file.write("Oranges")`
End of file	`file.endOfFile()`	`endOfFile = False`
Create a new file	`newFile("Shopping.txt")`	`file = open("shopping.txt","w")`
Append a file	`n/a`	`file = open("shopping.txt","a")`

Python example (reading data)

Employees	Text file
`file = open("employees.txt", "r") # open file in read mode` `endOfFile = False # set end of file to false` `while not endOfFile: # while not end of file` `name = file.readline() # read line 1` `department = file.readline() # read line 2` `salary = file.readline() # read line 3` `age = file.readline() # read line 4` `print("Name: ", name) # print name` `print("Department: ", department) # print department` `print("Salaray: ", salary) # print salary` `print("age: ", age) # print age` `if name == "": # if name is empty` `endOfFile = True # set end of file to true` `file.close() # close file`	Greg Sales 39000 43 Lucy Human resources 26750 28 Jordan Payroll 45000 31

Employees

Text file

file = open("employees.txt", "r") # open file in read mode
endOfFile = False # set end of file to false
while not endOfFile: # while not end of file
name = file.readline() # read line 1
department = file.readline() # read line 2
salary = file.readline() # read line 3
age = file.readline() # read line 4

print("Name: ", name) # print name
print("Department: ", department) # print department
print("Salaray: ", salary) # print salary
print("age: ", age) # print age

if name == "": # if name is empty
endOfFile = True # set end of file to true

file.close() # close file

Greg
Sales
39000
43
Lucy
Human resources
26750
28
Jordan
Payroll
45000
31

Python example (writing new data)

Employees

file = open("employees.txt", "a") # open file in append mode
file.write("Pollyn") # write line (n for new line)
file.write("Salesn")
file.write("26000n")
file.write("32n")

file.close() # close file

Greg
Sales
39000
43
Lucy
Human resources
26750
28
Jordan
Payroll
45000
31
Polly
Sales
26000
32

Examiner Tips and Tricks

When opening files it is really important to make sure you use the correct letter in the open command

“r” is for reading from a file only
“w” is for writing to a new file, if the file does not exist it will be created. If a file with the same name exists the contents will be overwritten
“a” is for writing to the end of an existing file only

Always make a backup of text files you are working with, one mistake and you can lose the contents!

Worked Example

Use pseudocode to write an algorithm that does the following :

Inputs the title and year of a book from the user.
Permanently stores the book title and year to the existing text file books.txt [4]

How to answer this question

Write two input statements (title and year of book)
Open the file
Write inputs to file
Close the file

Example answer

title = input("Enter title")

year = input("Enter year")

file = open("books.txt")

file.writeline(title)

file.writeline(year)

file.close()

Guidance

title = input("Enter title") 1 mark for both

year = input("Enter year")
file = open("books.txt") 1 mark

file.writeline(title) 1 mark for both