Chapter 14, Input/Output and Files

Program 14-5, Page Number: 424

# Files : Opening and Closing

# Open the file for writing

file_pointer = open("first_file","w")

print "Enter text:"

# Get characters and place them in the file

text = "BASIC is easy,\nFORTAN is fun,\nPascal may be structured,\nBut C's the one!"
print text
file_pointer.write(text)

file_pointer.close()

file_pointer = open("first_file","r")

#Display the text from file

print "\nYou entered:"
print file_pointer.read()

file_pointer.close()

Enter text:
BASIC is easy,
FORTAN is fun,
Pascal may be structured,
But C's the one!

You entered:
BASIC is easy,
FORTAN is fun,
Pascal may be structured,
But C's the one!

Program 14-6, Page Number: 426

# Using several files

# Open the source file for reading

first_file_pointer = open("first_file","r")

# Open the destination file for writing

second_file_pointer = open("second_file","w")

# Transfer characters from source to destination file

c = first_file_pointer.read()
second_file_pointer.write(c)

# Close both files

first_file_pointer.close()
second_file_pointer.close()

# Open second file for displaying contentes

second_file_pointer = open("second_file","r")
print("'second_file' contains:")
print second_file_pointer.read()

'second_file' contains:
BASIC is easy,
FORTAN is fun,
Pascal may be structured,
But C's the one!

Program 14-7, Page Number : 428

# Append mode

# Open the first file for writing

first_file_pointer = open("first_file","w")

# Open the second file for appending

second_file_pointer = open("second_file","a")

# Writing to both files

first_file_pointer.write("\n--Anonymous\n")
second_file_pointer.write("\n--Anonymous\n")

# Close both files

first_file_pointer.close()
second_file_pointer.close()

# Display the contents of first file
first_file_pointer = open("first_file","r")
print("After write, 'first_file contains:")
print first_file_pointer.read()

# Display the contents of second file
second_file_pointer = open("second_file","r")
print("After append, 'second_file' contains:")
print second_file_pointer.read()

After write, 'first_file contains:

--Anonymous

After append, 'second_file' contains:
BASIC is easy,
FORTAN is fun,
Pascal may be structured,
But C's the one!
--Anonymous

Program 14-8, Page Number: 431

# The seek function

# Open file for reading
try :
	file_pointer = open("second_file","r")
except :
	print "'second_file' cannot be opened"
	exit ()

# Skip the first 6 characters

file_pointer.seek(6,0)
print file_pointer.read()

is easy,
FORTAN is fun,
Pascal may be structured,
But C's the one!
--Anonymous

Program 14-9, Page Number: 433

# The 'w+' mode and seek to rewind a file

# Open a file for read/write
file_pointer = open("first_file","w+")

print "Enter text:"
text = "BASIC is easy,\nFORTAN is fun,\nPascal may be structured,\nBut C's the one!"
print text
file_pointer.write(text)

file_pointer.seek(0,0)

# Display the file
print "\nYou entered:"
print file_pointer.read()

Enter text:
BASIC is easy,
FORTAN is fun,
Pascal may be structured,
But C's the one!

You entered:
BASIC is easy,
FORTAN is fun,
Pascal may be structured,
But C's the one!