Programs on Python File Handling

Programs on Python File Handling:

1.Write a program to display all the records in a file “python.txt” along with line/record number?

Ans.  

fh=open("python.txt","r")
count=0
rec=""
while True:
    rec=fh.readline()
    if rec=="":
        break
    count=count+1
    print(count,rec)
fh.close()

2.A text file “PYTHON.TXT” contains alphanumeric text. Write a program that reads this text file and prints only the numbers or digits in the file.

Ans.

fh=open(“python.txt","r")                                                     
rec=fh.read();
for a in rec:
    if a.isdigit():
        print(a,end=' ')
fh.close()

3.Write a function LongLine() that accepts a filename and prints the file’s longest line with its length?    

Ans.

def get_longest_line(filename):
    mydict = {}
 
    for line in open(filename, 'r'):
        mydict[len(line)] = line
 
    return mydict[sorted(mydict)[-1]]
get_longest_line('car.txt')

4.Write a program to count the number of upper-case alphabets present in a text file          “PYTHON.TXT”

Ans.

def uppercount():
    upper=0
    f1=open("PYTHON.txt",'r')
    line=f1.read()
    for i in line:
        if (i.isupper()):
            upper+=1
    print("Total no. of upper-case alphabets :",upper)
uppercount()

5.Write a program to count the words “to” and “the” present in a text file  “python.txt”.

Ans.

fname = "python.txt"
 num_words = 0
 with open(fname, 'r') as f:
    for line in f:                        
        words = line.split()
        num_words += len(words)
print("Number of words:")
print(num_words)

6.Given a text file car.txt following information of car  ‘carNo,carname,containing mileage’. Write a python function to display details of all those cars whose mileage is fron 100 to 150.

Ans.  

def display():
    file=open("car.txt",'r')
    lines=file.readlines()
    file.close()
    for line in lines:
        x=line.split(',')
        mileage=(int) (x[2])
        if mileage>100 and mileage<=150:
            print(line)
display()

7.Write a program to print following type of statistics for the given file.

A text file ‘car.txt’ contain following information of car carNo,carname,containing mileage. Write a python function to display :

• Number of lines in the file
• Number of empty lines
• Average characters per non-empty line

Ans.  

fp1=open("car.txt","r")
lines=fp1.readlines()
totallines=len(lines)
blank=0
char=0
for i in lines:
    char+=len(i) 
    i = i.strip()
    if len(i)==0:
        blank+=1
fp1.close()
print (totallines,"lines in the file")
print (blank,"Empty lines")
print (char/(totallines-blank),"average characters per non-empty line")