58.1.1. File Open statement
(b) The mode argument tells how the file is to be opened, e.g. for reading only, for writing only etc.
(d) If we do not specify any path, the file is assumed to be in the current directory
58.1.2. Binary files Vs Text files
(b) Student data containing name(string), age(integer), percentage (float) should be stored as a binary file
(d) Binary data is read and written in bytes objects and cannot be printed directly
58.1.3. Binary files Vs Text files
(c) Write only with error if file is existing
58.1.4. Different File Operations
# Open the file for read
fr = open('TextData.txt', 'r')
# Open the file for write (new file)
fw = open('NewFile.txt', 'w')
# Read the file and copy it to the new file
fw.write(fr.read())
fr.close() # Close the input file
fw.close() # Close the new file
# Open the new file as read / write
fr1 = open('NewFile.txt', 'r+')
# read and print the first 12 characters
print(fr1.read(12))
# Print the cursor position
print(fr1.tell())
# Write some text of 20 characters at the end
print(fr1.write("this is the new text"))
# Position the cursor at 12
print(fr1.seek(12))
# Read and print the next character (at cursor position 12)
print(fr1.read(1))
# Position the cursor at 15
print(fr1.seek(15))
# Read and print 10 characters from this position
print(fr1.read(10))
# read() always reads the entire file irrespective of cursor position and changes the cursor position to the end
print(fr1.read())
fr1.close() # Closing the file
58.1.5. Understanding Binary Files
#imports the pickle library
import pickle
Students = [['John', '501', 20, 92.5],
['Kohli', '502', 21, 95.5],
['Ganga','503', 20, 90.5],
['Gayathri','504', 20, 82.5],
['Krishna','505', 20, 96.5]]
# Open the output file with binary format
fst = open("students.dat",'wb')
for student in Students:
pickle.dump(student,fst) #Fill the missing code to write the details of each student
#Closing the output filr
fst.close()
#Opening the file as input binary
fst = open("students.dat",'rb')
#Fill the missing code to read the file record
data = pickle.load(fst)
#The Endof file is indicated as EOFError exception, we need to catch this exception
try:
while(True):
print(data)
data = pickle.load(fst)
except:
print("Bye")
58.1.6. print each line of a file in reverse order.
#take the input file name
i = input("Enter file name: ")
#open the file in read only mode
fin = open(i,"r")
# Iterate over the lines and print them in reverse order
for i in range(7):
a = fin.readline()
print(a.strip()[::-1])
#close the file
fin.close()
58.1.7. Print the number of lines, words, and characters in a file.
#take the input file name
i = input("Enter file name: ")
#open the file in read only mode
fin = open(i, "r")
charCount = wordCount = lineCount = 0
for line in fin: #Read each Line
lineCount += 1
# write your logic here
wordCount += len(line.split(' '))
charCount += len(line)
print("Line count =", lineCount) #Print the Counts
print("Word count =", wordCount)
print("Char count =", charCount)
#close the file
fin.close()
58.1.8. Copy contents of one file to another file
file = input("Enter file name: ")
fin = open(file, 'r')
fout = open('OutputData3.txt',"w")
#write your code here..
fout.write(fin.read())
fin.close()
fout.close()
fin2 = open('OutputData3.txt','r')
print(fin2.read())
fin2.close()
