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Programming File Handling Edexcel

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Exam code:1CP2

Programming 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	Python
Open	`file = open("fruit.txt","r")`
Close	`file.close()`
Read line	`file.readline()`
Write line	`file.write("Oranges")`
End of file	`endOfFile = False`
Create a new file	`file = open("shopping.txt","w")`
Append a file	`file = open("shopping.txt","a")`

The same approach for opening and writing to comma separated value files (CSV) can be used
When opening a CSV file, the file extension would change to “.csv“
- file = open("fruit.csv","r")

What are the differences when file handling?

Concept	What it means
Open	`Opens the file in memory to be used in the program`
Close	`Closes the file` `This must be done to store any content that has been written or appended to it`
Read	`Opens the file in read-only mode` `The contents can be read but not changed`
Write	`Opens the file in write mode` `The contents of the file will be over-written` `No prior content in the file will be saved`
Append a file	`Opens the file in append mode` `New data will be added to the end of the file` `Previous data in the file will remain`

Python example (reading data from a text file)

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 (reading data from a csv file)

Employees	CSV file
`import csv` # Open the CSV file `with open('employees.csv', 'r') as csv_file:` `csv_reader = csv.reader(csv_file)` # Iterate over each row in the CSV file `for row in csv_reader:` `print(row)`	Greg, Sales, 39000, 43 Lucy, Human resources, 26750, 28 Jordan, Payroll, 45000, 31

Employees

CSV file

import csv

# Open the CSV file

with open('employees.csv', 'r') as csv_file:

csv_reader = csv.reader(csv_file)

# Iterate over each row in the CSV file

for row in csv_reader:

print(row)

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

Python example (writing new data to a text file)

Employees	Text file
`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

Employees

Text file

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

Python example (writing new data to a csv file)

Employees	CSV file
`import csv` # Sample data to write to CSV `employees_data = [` `['John', 'Sales', 50000, 30], ['Jane', 'Marketing', 60000, 35], ['Alice', 'Engineering', 70000, 40]` `]` # Write data to CSV file `with open('employees.csv', 'w', newline='') as csv_file:` `csv_writer = csv.writer(csv_file)` `csv_writer.writerows(employees_data)` `print("Data has been written to employees.csv")`	John, Sales, 50000, 30, Jane, Marketing, 60000, 35 Alice, Engineering, 70000, 40

Employees

CSV file

import csv

# Sample data to write to CSV

employees_data = [

['John', 'Sales', 50000, 30], ['Jane', 'Marketing', 60000, 35], ['Alice', 'Engineering', 70000, 40]

]

# Write data to CSV file

with open('employees.csv', 'w', newline='') as csv_file:

csv_writer = csv.writer(csv_file)

csv_writer.writerows(employees_data)

print("Data has been written to employees.csv")

John, Sales, 50000, 30,

Jane, Marketing, 60000, 35

Alice, Engineering, 70000, 40

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()

Marks

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
- file.writeline(year)
file.close() 1 mark

Computer Science GCES EDEXCEL

Programming File Handling Edexcel

Programming File Handling

What is file handling?

What are the differences when file handling?

Python example (reading data from a text file)

Python example (reading data from a csv file)

Python example (writing new data to a text file)

Python example (writing new data to a csv file)

Examiner Tips and Tricks

Worked Example

Responses