8. Other functions
To read contents from file
1. fp.read(n) :- n is the number of bytes to read
2. fp.readline():- It will read only one line that is
point by fp.
3. fp.readlines(): It will all the lines of the file and
store all the lines in list
To write contents into the file
1. fp.writelines(l):- It will write all the lines present
in the list l
9. Programs
1. WAP to write starting 10 even numbers in the
output file output1.txt ( in single line)
2. WAP to write starting 10 odd numbers in the
output file output2.txt ( in multiple lines)
3. WAP to write 5 random numbers between 50-
60(both inclusive) in the output file output3.txt ( in
single line)
4. WAP that reads data from a file and calculates the
percentage of vowels and consonants in the file
10. Prgrams
5. WAP that accepts filename as an input from the
user. Open the file and count the number of times
a character(I/P from user) appears in the file
6. WAP that copies one Python Script into another in
such a way that all comment lines are skipped and
not copied in the destination file.
7. WAP to enter the name of the file and print the
longest line present in the file.
11. 8. Write a Python program to read a file (“input.txt”) of
oil prices in England , Australia and India. Output the
average oil price of each country to an output file
output.txt.(Note: All fields are separated with one
space)
12. Modes of opening the file
Text File Binary File
r rb
w wb
a ab
r+ rb+
w+ wb+
a+ ab+
x xb
13. with keyword
We can open the file using with keyword.
Example:
s=fp.read()
The advantage of using with keyword is “File is
properly closed after it is used even if an error
occurs during read or write operation or even when
you forget to explicitly close the file”
with open(“a.txt“,”r”) as fp:
s=fp.read()
print(s)
14. Other useful File methods
fp.fileno() :- It returns the file number of the file (File
Descriptor)
fp.truncate(n) :- Resizes the file to n bytes
fp.tell():- It tells the current position of the file
pointer
fp.seek(byteoffset,reference) :-It is used to move
the file pointer fp to a new location.
15. Assignment
1. WAP that reads a file line by line. Each line read from the file is copied to
another file with line numbers specified at the beginning of the line.
For example, if contents of file is as follows:
Hello
Bye
GLA
Expected O/P:
1. Hello
2. Bye
3. GLA
16. 2. WAP that counts the number of tabs, spaces and
newline characters in a file
3. WAP that counts the number of characters, words and
lines in a file
4. WAP that generates a Quiz and uses two files-
Questions.txt and Answers.txt . The program opens
Questions.txt and reads a question and displays the
question with options on the screen. The program then
opens the Answers.txt file and displays the correct
answers.
17. 5. WAP to read first n lines from the file.
6. WAP to read last n lines from the file.
7. WAP to read from m line to n line.
8. WAP to write all the prime numbers from 2 to 100
to the output file output1.txt
9. WAP to append all the armstrong numbers from
100 to 999 to the above file outfile1.txt
18. 10. WAP to write only those lines in the output file that starts with 172
Input File
Hello Raj
172.16.42.35
165.72.42.1
127.0.01
172.12.12.10
17.13.11.10
Expected O/P:
172.16.42.35
172.12.12.10
