Modify the inventory program of Exercise 14.5. The modified program allows you to delete a record for a tool that you no longer have and allows you to update any information in the file.

Question

What will be an ideal response?

Answer 1

```
# Hardware inventory.

import sys
import shelve

# prompt for an input menu choice
def enterChoice():

print "\nEnter your choice"
print "1 - add a new tool"
print "2 - list tools"
print "3 - update record"
print "4 - delete record"
print "5 - end program"

while 1:
menuChoice = int( raw_input( "? " ) )

if not 1 <= menuChoice <= 5:
print >> sys.stderr, "Incorrect choice"

else:
break

return menuChoice

# add item to shelve file
def addItem( inventory ):

toolID = int( raw_input( "Enter tool identification number: " ) )

if 0 < toolID <= 100:
userInput = raw_input( "Enter: tool quantity cost\n? " )
inventory[ str( toolID ) ] = userInput.split()
else:
print "Invalid record number."

# list tools
def listTools( inventory ):

print "ToolID".ljust( 10 ),
print "Tools".ljust( 10 ),
print "Quantity".ljust( 10 ),
print "Price".ljust( 10 )

for key in inventory.keys():
print key.ljust( 10 ),
print inventory[ key ][ 0 ].ljust( 10 ),
print inventory[ key ][ 1 ].ljust( 10 ),
print inventory[ key ][ 2 ].ljust( 10 )

# delete tool
def deleteTool( inventory ):

toolID = raw_input( "Enter toolID number: " )

if inventory.has_key( toolID ):
del inventory[ str( toolID ) ]
else:
print >> sys.stderr, "Tool ID", toolID, \
"does not exist."

# update item
def updateItem( inventory ):

selection = ""

toolID = raw_input( "Enter ID number of tool to be updated: " )

if inventory.has_key( toolID ):
tempRecord = inventory[ toolID ] # copy of record

print """
Select an item to update.
[0] Tool Name
[1] Quantity
[2] Price"""

selection = raw_input( "Enter a selection: " )

# change indicated item
if selection == "0":
tempRecord[ 0 ] = raw_input( "Enter new tool name: " )

if selection == "1":
tempRecord[ 1 ] = raw_input( "Enter new quantity: " )

if selection == "2":
tempRecord[ 2 ] = raw_input( "Enter new price: " )

# delete old record and add updated one
if 0 <= int( selection ) <= 2:
del inventory[ toolID ]
inventory[ toolID ] = tempRecord
else:
print >> sys.stderr, "Tool ID", toolID, \
"does not exist."

options = [ addItem, listTools, updateItem, deleteTool ]

# open shelve file
try:
inventory = shelve.open( "hardware.dat" )
except IOError:
print >> sys.stderr, "File could not be opened"
sys.exit( 1 )

# process user commands
while 1:

choice = enterChoice()

if choice == 5:
break

options[ choice - 1 ]( inventory )

inventory.close()
```
Enter your choice
1 - add a new tool
2 - list tools
3 - update record
4 - delete record
5 - end program
? 2
ToolID Tools Quantity Price
88 saw 34 18.50
21 wrench 45 8.00
Enter your choice
1 - add a new tool
2 - list tools
3 - update record
4 - delete record
5 - end program
? 3
Enter ID number of tool to be updated: 21
Select an item to update.
[0] Tool Name
[1] Quantity
[2] Price
Enter a selection: 2
Enter new price: 10.00
Enter your choice
1 - add a new tool
2 - list tools
3 - update record
4 - delete record
5 - end program
? 4
Enter toolID number: 88
Enter your choice
1 - add a new tool
2 - list tools
3 - update record
4 - delete record
5 - end program
? 2
ToolID Tools Quantity Price
21 wrench 45 10.00
Enter your choice
1 - add a new tool
2 - list tools
3 - update record
4 - delete record
5 - end program
? 5