Using cPickle

Hi there,

I have to make a small database using cPickle. I'm having troubles
trying to read in the information if it's more than one line. I'm
pretty sure it's in the line "for line in stuff:" Can anyone help me
out? Basically the end result is wanting it to look something like
what is down below when list is typed in:

Last name First Name Email Address
Doe John

# @author: Ocdt Murray McClafferty 24656
# This will manage a small database using the cPickle module.
# It must maintain a list of last names, first names and email
addresses, and must let a user interact with the program

#
#!usr/bin/python
# -*- coding: utf-8 -*-

import sys
import cPickle

#
format = '%s             %s                  %s'

try:
	filename = sys.argv[1]
	input = open(filename, 'r')

except IOError:
	print 'File is not available, will create a new file now'
	lastName='Last Name'
	firstName='First Name'
	email= 'Email'
	#input.close()
	output=open (filename, 'w')
	total = format%(lastName, firstName, email)
	cPickle.dump(total,output)
	#cPickle.dump(firstName,output)
	#cPickle.dump(email,output)
	output.close()
except EOFError:
	print 'File is empty'

#datas = cPickle.load(input)

while True:
	command=sys.stdin.readline()[:-1]
	if command=='list': #lists the data in the file
		input = open(filename, 'r')
		stuff=cPickle.load(input)
		for line in stuff:
			#firstName=cPickle.load(input)
			#email=cPickle.load(input)
			#print repr (lastName).rjust(10), repr(firstName).rjust(20), repr
(email).rjust(20)
			stuff=cPickle.load(input)
			print stuff
			print line

		input.close()

	if command=='exit' or command=='quit' : #NEVER forget the exit!!!
		print 'Save changes? y for Yes, n for No'
		commandSave=sys.stdin.readline()[:-1]
		if commandSave =='y': #if the user wants to save
			output=open(filename, 'w')
			cPickle.dump(work,output)
			output.close()
			sys.exit(0)
		if commandSave =='n': #no save
			input.close()
			sys.exit(0)

	if command=='add': #adds an entity to the file
		print 'Last name?'
		lastName=sys.stdin.readline()[:-1]
		print 'First name?'
		firstName=sys.stdin.readline()[:-1]
		print 'Email address?'
		email=sys.stdin.readline()[:-1]
		work = format%(lastName, firstName, email)
		#output=open(filename, 'w')
		#data=cPickle.load(output)
		#data.append(work)
		#output.close()
		output=open(filename, 'a')
		cPickle.dump(work,output)
		output.close()

All help would be appreciated. I am new to Python and this seems to be
quite a challenge for me.

mmcclaf

mmcclaf wrote:
> Hi there,
>
> I have to make a small database using cPickle. I'm having troubles
> trying to read in the information if it's more than one line. I'm
> pretty sure it's in the line "for line in stuff:" Can anyone help me
> out? Basically the end result is wanting it to look something like
> what is down below when list is typed in:
>
> Last name First Name Email Address
> Doe John
>
>
>
>

> # @author: Ocdt Murray McClafferty 24656
> # This will manage a small database using the cPickle module.
> # It must maintain a list of last names, first names and email
> addresses, and must let a user interact with the program
> 
> #
> #!usr/bin/python
> # -*- coding: utf-8 -*-
> 
> import sys
> import cPickle
> 
> #
> format = '%s             %s                  %s'
> 
> try:
> 	filename = sys.argv[1]
> 	input = open(filename, 'r')
> 
> except IOError:
> 	print 'File is not available, will create a new file now'
> 	lastName='Last Name'
> 	firstName='First Name'
> 	email= 'Email'
> 	#input.close()
> 	output=open (filename, 'w')
> 	total = format%(lastName, firstName, email)
> 	cPickle.dump(total,output)
> 	#cPickle.dump(firstName,output)
> 	#cPickle.dump(email,output)
> 	output.close()
> except EOFError:
> 	print 'File is empty'
> 
> #datas = cPickle.load(input)
> 
> while True:
> 	command=sys.stdin.readline()[:-1]
> 	if command=='list': #lists the data in the file
> 		input = open(filename, 'r')
> 		stuff=cPickle.load(input)
> 		for line in stuff:
> 			#firstName=cPickle.load(input)
> 			#email=cPickle.load(input)
> 			#print repr (lastName).rjust(10), repr(firstName).rjust(20), repr
> (email).rjust(20)
> 			stuff=cPickle.load(input)
> 			print stuff
> 			print line
> 
> 		input.close()
> 
> 	if command=='exit' or command=='quit' : #NEVER forget the exit!!!
> 		print 'Save changes? y for Yes, n for No'
> 		commandSave=sys.stdin.readline()[:-1]
> 		if commandSave =='y': #if the user wants to save
> 			output=open(filename, 'w')
> 			cPickle.dump(work,output)
> 			output.close()
> 			sys.exit(0)
> 		if commandSave =='n': #no save
> 			input.close()
> 			sys.exit(0)
> 
> 	if command=='add': #adds an entity to the file
> 		print 'Last name?'
> 		lastName=sys.stdin.readline()[:-1]
> 		print 'First name?'
> 		firstName=sys.stdin.readline()[:-1]
> 		print 'Email address?'
> 		email=sys.stdin.readline()[:-1]
> 		work = format%(lastName, firstName, email)
> 		#output=open(filename, 'w')
> 		#data=cPickle.load(output)
> 		#data.append(work)
> 		#output.close()
> 		output=open(filename, 'a')
> 		cPickle.dump(work,output)
> 		output.close()
> 
> 

>
> All help would be appreciated. I am new to Python and this seems to be
> quite a challenge for me.

Make sure you use modes "rb" and "wb" when you open the pickle files. If
you are running on Windows this can make a difference.

regards
Steve
--
Steve Holden +1 571 484 6266 +1 800 494 3119
Holden Web LLC http://www.holdenweb.com/

Steve Holden

On Feb 6, 10:25*am, Steve Holden <st...@holdenweb.com> wrote:
> mmcclaf wrote:
> > Hi there,
>
> > I have to make a small database using cPickle. I'm having troubles
> > trying to read in the information if it's more than one line. I'm
> > pretty sure it's in the line "for line in stuff:" Can anyone help me
> > out? Basically the end result is wanting it to look something like
> > what is down below when list is typed in:
>
> > Last name * * * * * * * * First Name * * * * * * * *Email Address
> > Doe * * * * * * * * * * * * *John
> > j...@doe.com
>
> >

> > # @author: Ocdt Murray McClafferty 24656
> > # This will manage a small database using the cPickle module.
> > # It must maintain a list of last names, first names and email
> > addresses, and must let a user interact with the program

>
> > #
> > #!usr/bin/python
> > # -*- coding: utf-8 -*-
>
> > import sys
> > import cPickle
>
> > #
> > format = '%s * * * * * * %s * * * * * * * * *%s'
>
> > try:
> > * *filename = sys.argv[1]
> > * *input = open(filename, 'r')
>
> > except IOError:
> > * *print 'File is not available, will create a new file now'
> > * *lastName='Last Name'
> > * *firstName='First Name'
> > * *email= 'Email'
> > * *#input.close()
> > * *output=open (filename, 'w')
> > * *total = format%(lastName, firstName, email)
> > * *cPickle.dump(total,output)
> > * *#cPickle.dump(firstName,output)
> > * *#cPickle.dump(email,output)
> > * *output.close()
> > except EOFError:
> > * *print 'File is empty'
>
> > #datas = cPickle.load(input)
>
> > while True:
> > * *command=sys.stdin.readline()[:-1]
> > * *if command=='list': #lists the data in the file
> > * * * * * *input = open(filename, 'r')
> > * * * * * *stuff=cPickle.load(input)
> > * * * * * *for line in stuff:
> > * * * * * * * * * *#firstName=cPickle.load(input)
> > * * * * * * * * * *#email=cPickle.load(input)
> > * * * * * * * * * *#print repr (lastName).rjust(10), repr(firstName).rjust(20), repr
> > (email).rjust(20)
> > * * * * * * * * * *stuff=cPickle.load(input)
> > * * * * * * * * * *print stuff
> > * * * * * * * * * *print line
>
> > * * * * * *input.close()
>
> > * *if command=='exit' or command=='quit' : #NEVER forget the exit!!!
> > * * * * * *print 'Save changes? y for Yes, n for No'
> > * * * * * *commandSave=sys.stdin.readline()[:-1]
> > * * * * * *if commandSave =='y': #if the user wants to save
> > * * * * * * * * * *output=open(filename, 'w')
> > * * * * * * * * * *cPickle.dump(work,output)
> > * * * * * * * * * *output.close()
> > * * * * * * * * * *sys.exit(0)
> > * * * * * *if commandSave =='n': #no save
> > * * * * * * * * * *input.close()
> > * * * * * * * * * *sys.exit(0)
>
> > * *if command=='add': #adds an entity to the file
> > * * * * * *print 'Last name?'
> > * * * * * *lastName=sys.stdin.readline()[:-1]
> > * * * * * *print 'First name?'
> > * * * * * *firstName=sys.stdin.readline()[:-1]
> > * * * * * *print 'Email address?'
> > * * * * * *email=sys.stdin.readline()[:-1]
> > * * * * * *work = format%(lastName, firstName, email)
> > * * * * * *#output=open(filename, 'w')
> > * * * * * *#data=cPickle.load(output)
> > * * * * * *#data.append(work)
> > * * * * * *#output.close()
> > * * * * * *output=open(filename, 'a')
> > * * * * * *cPickle.dump(work,output)
> > * * * * * *output.close()
>
> > 

>
> > All help would be appreciated. I am new to Python and this seems to be
> > quite a challenge for me.
>
> Make sure you use modes "rb" and "wb" when you open the pickle files. If
> you are running on Windows this can make a difference.
>
> regards
> *Steve
> --
> Steve Holden * * * *+1 571 484 6266 * +1 800 494 3119
> Holden Web LLC * * * * * * *http://www.holdenweb.com/

I've tried both rb and wb as well as r and w, there appears to be no
difference in the running of the code.

mmcclaf

mmcclaf wrote:
> On Feb 6, 10:25 am, Steve Holden <st...@holdenweb.com> wrote:
>> mmcclaf wrote:
>>> Hi there,
>>> I have to make a small database using cPickle. I'm having troubles
>>> trying to read in the information if it's more than one line. I'm
>>> pretty sure it's in the line "for line in stuff:" Can anyone help me
>>> out? Basically the end result is wanting it to look something like
>>> what is down below when list is typed in:
>>> Last name First Name Email Address
>>> Doe John
>>> j...@doe.com
>>>

>>> # @author: Ocdt Murray McClafferty 24656
>>> # This will manage a small database using the cPickle module.
>>> # It must maintain a list of last names, first names and email
>>> addresses, and must let a user interact with the program
>>> #
>>> #!usr/bin/python
>>> # -*- coding: utf-8 -*-
>>> import sys
>>> import cPickle
>>> #
>>> format = '%s             %s                  %s'
>>> try:
>>>    filename = sys.argv[1]
>>>    input = open(filename, 'r')
>>> except IOError:
>>>    print 'File is not available, will create a new file now'
>>>    lastName='Last Name'
>>>    firstName='First Name'
>>>    email= 'Email'
>>>    #input.close()
>>>    output=open (filename, 'w')
>>>    total = format%(lastName, firstName, email)
>>>    cPickle.dump(total,output)
>>>    #cPickle.dump(firstName,output)
>>>    #cPickle.dump(email,output)
>>>    output.close()
>>> except EOFError:
>>>    print 'File is empty'
>>> #datas = cPickle.load(input)
>>> while True:
>>>    command=sys.stdin.readline()[:-1]
>>>    if command=='list': #lists the data in the file
>>>            input = open(filename, 'r')
>>>            stuff=cPickle.load(input)
>>>            for line in stuff:
>>>                    #firstName=cPickle.load(input)
>>>                    #email=cPickle.load(input)
>>>                    #print repr (lastName).rjust(10), repr(firstName).rjust(20), repr
>>> (email).rjust(20)
>>>                    stuff=cPickle.load(input)
>>>                    print stuff
>>>                    print line
>>>            input.close()
>>>    if command=='exit' or command=='quit' : #NEVER forget the exit!!!
>>>            print 'Save changes? y for Yes, n for No'
>>>            commandSave=sys.stdin.readline()[:-1]
>>>            if commandSave =='y': #if the user wants to save
>>>                    output=open(filename, 'w')
>>>                    cPickle.dump(work,output)
>>>                    output.close()
>>>                    sys.exit(0)
>>>            if commandSave =='n': #no save
>>>                    input.close()
>>>                    sys.exit(0)
>>>    if command=='add': #adds an entity to the file
>>>            print 'Last name?'
>>>            lastName=sys.stdin.readline()[:-1]
>>>            print 'First name?'
>>>            firstName=sys.stdin.readline()[:-1]
>>>            print 'Email address?'
>>>            email=sys.stdin.readline()[:-1]
>>>            work = format%(lastName, firstName, email)
>>>            #output=open(filename, 'w')
>>>            #data=cPickle.load(output)
>>>            #data.append(work)
>>>            #output.close()
>>>            output=open(filename, 'a')
>>>            cPickle.dump(work,output)
>>>            output.close()
>>> 

>>> All help would be appreciated. I am new to Python and this seems to be
>>> quite a challenge for me.
>> Make sure you use modes "rb" and "wb" when you open the pickle files. If
>> you are running on Windows this can make a difference.
>>
>> regards
>> Steve
>> --
>> Steve Holden +1 571 484 6266 +1 800 494 3119
>> Holden Web LLC http://www.holdenweb.com/
>
> I've tried both rb and wb as well as r and w, there appears to be no
> difference in the running of the code.
>
"cPickle.dump(work,output)" writes a string and
"stuff=cPickle.load(input)" just reads that string, so "for line in
stuff:" is iterating through the characters if the string. You need to
use cPickle.load() to read each string (line).

MRAB

On Feb 6, 3:09*pm, MRAB <goo...@mrabarnett.plus.com> wrote:
> mmcclaf wrote:
> > On Feb 6, 10:25 am, Steve Holden <st...@holdenweb.com> wrote:
> >> mmcclaf wrote:
> >>> Hi there,
> >>> I have to make a small database using cPickle. I'm having troubles
> >>> trying to read in the information if it's more than one line. I'm
> >>> pretty sure it's in the line "for line in stuff:" Can anyone help me
> >>> out? Basically the end result is wanting it to look something like
> >>> what is down below when list is typed in:
> >>> Last name * * * * * * * * First Name * * * * * * * *Email Address
> >>> Doe * * * * * * * * * * * * *John
> >>> j...@doe.com
> >>>

> >>> # @author: Ocdt Murray McClafferty 24656
> >>> # This will manage a small database using the cPickle module.
> >>> # It must maintain a list of last names, first names and email
> >>> addresses, and must let a user interact with the program
> >>> #
> >>> #!usr/bin/python
> >>> # -*- coding: utf-8 -*-
> >>> import sys
> >>> import cPickle
> >>> #
> >>> format = '%s * * * * * * %s * * * * * * * * *%s'
> >>> try:
> >>> * *filename = sys.argv[1]
> >>> * *input = open(filename, 'r')
> >>> except IOError:
> >>> * *print 'File is not available, will create a new file now'
> >>> * *lastName='Last Name'
> >>> * *firstName='First Name'
> >>> * *email= 'Email'
> >>> * *#input.close()
> >>> * *output=open (filename, 'w')
> >>> * *total = format%(lastName, firstName, email)
> >>> * *cPickle.dump(total,output)
> >>> * *#cPickle.dump(firstName,output)
> >>> * *#cPickle.dump(email,output)
> >>> * *output.close()
> >>> except EOFError:
> >>> * *print 'File is empty'
> >>> #datas = cPickle.load(input)
> >>> while True:
> >>> * *command=sys.stdin.readline()[:-1]
> >>> * *if command=='list': #lists the data in the file
> >>> * * * * * *input = open(filename, 'r')
> >>> * * * * * *stuff=cPickle.load(input)
> >>> * * * * * *for line in stuff:
> >>> * * * * * * * * * *#firstName=cPickle.load(input)
> >>> * * * * * * * * * *#email=cPickle.load(input)
> >>> * * * * * * * * * *#print repr (lastName).rjust(10), repr(firstName).rjust(20), repr
> >>> (email).rjust(20)
> >>> * * * * * * * * * *stuff=cPickle.load(input)
> >>> * * * * * * * * * *print stuff
> >>> * * * * * * * * * *print line
> >>> * * * * * *input.close()
> >>> * *if command=='exit' or command=='quit' : #NEVER forget the exit!!!
> >>> * * * * * *print 'Save changes? y for Yes, n for No'
> >>> * * * * * *commandSave=sys.stdin.readline()[:-1]
> >>> * * * * * *if commandSave =='y': #if the user wants to save
> >>> * * * * * * * * * *output=open(filename, 'w')
> >>> * * * * * * * * * *cPickle.dump(work,output)
> >>> * * * * * * * * * *output.close()
> >>> * * * * * * * * * *sys.exit(0)
> >>> * * * * * *if commandSave =='n': #no save
> >>> * * * * * * * * * *input.close()
> >>> * * * * * * * * * *sys.exit(0)
> >>> * *if command=='add': #adds an entity to the file
> >>> * * * * * *print 'Last name?'
> >>> * * * * * *lastName=sys.stdin.readline()[:-1]
> >>> * * * * * *print 'First name?'
> >>> * * * * * *firstName=sys.stdin.readline()[:-1]
> >>> * * * * * *print 'Email address?'
> >>> * * * * * *email=sys.stdin.readline()[:-1]
> >>> * * * * * *work = format%(lastName, firstName, email)
> >>> * * * * * *#output=open(filename, 'w')
> >>> * * * * * *#data=cPickle.load(output)
> >>> * * * * * *#data.append(work)
> >>> * * * * * *#output.close()
> >>> * * * * * *output=open(filename, 'a')
> >>> * * * * * *cPickle.dump(work,output)
> >>> * * * * * *output.close()
> >>> 

> >>> All help would be appreciated. I am new to Python and this seems to be
> >>> quite a challenge for me.
> >> Make sure you use modes "rb" and "wb" when you open the pickle files. If
> >> you are running on Windows this can make a difference.
>
> >> regards
> >> *Steve
> >> --
> >> Steve Holden * * * *+1 571 484 6266 * +1 800 494 3119
> >> Holden Web LLC * * * * * * *http://www.holdenweb.com/
>
> > I've tried both rb and wb as well as r and w, there appears to be no
> > difference in the running of the code.
>
> "cPickle.dump(work,output)" writes a string and
> "stuff=cPickle.load(input)" just reads that string, so "for line in
> stuff:" is iterating through the characters if the string. You need to
> use cPickle.load() to read each string (line).

Ok, so I just modified that section to:

	if command=='list': #lists the data in the file
		input = open(filename, 'r')
		stuff=cPickle.load(input)
		for line in stuff:
			#firstName=cPickle.load(input)
			#email=cPickle.load(input)
			#print repr (lastName).rjust(10), repr(firstName).rjust(20), repr
(email).rjust(20)
			stuff=cPickle.load(input)
			print stuff


		input.close()

And now it's printing it out ok, but then I get an EOFError at
stuff=cPickle.load(onput) at line 45.

mmcclaf

mmcclaf wrote:
> On Feb 6, 3:09 pm, MRAB <goo...@mrabarnett.plus.com> wrote:
>> mmcclaf wrote:
>>> On Feb 6, 10:25 am, Steve Holden <st...@holdenweb.com> wrote:
>>>> mmcclaf wrote:
>>>>> Hi there,
>>>>> I have to make a small database using cPickle. I'm having troubles
>>>>> trying to read in the information if it's more than one line. I'm
>>>>> pretty sure it's in the line "for line in stuff:" Can anyone help me
>>>>> out? Basically the end result is wanting it to look something like
>>>>> what is down below when list is typed in:
>>>>> Last name First Name Email Address
>>>>> Doe John
>>>>> j...@doe.com
>>>>>

>>>>> # @author: Ocdt Murray McClafferty 24656
>>>>> # This will manage a small database using the cPickle module.
>>>>> # It must maintain a list of last names, first names and email
>>>>> addresses, and must let a user interact with the program
>>>>> #
>>>>> #!usr/bin/python
>>>>> # -*- coding: utf-8 -*-
>>>>> import sys
>>>>> import cPickle
>>>>> #
>>>>> format = '%s             %s                  %s'
>>>>> try:
>>>>>    filename = sys.argv[1]
>>>>>    input = open(filename, 'r')
>>>>> except IOError:
>>>>>    print 'File is not available, will create a new file now'
>>>>>    lastName='Last Name'
>>>>>    firstName='First Name'
>>>>>    email= 'Email'
>>>>>    #input.close()
>>>>>    output=open (filename, 'w')
>>>>>    total = format%(lastName, firstName, email)
>>>>>    cPickle.dump(total,output)
>>>>>    #cPickle.dump(firstName,output)
>>>>>    #cPickle.dump(email,output)
>>>>>    output.close()
>>>>> except EOFError:
>>>>>    print 'File is empty'
>>>>> #datas = cPickle.load(input)
>>>>> while True:
>>>>>    command=sys.stdin.readline()[:-1]
>>>>>    if command=='list': #lists the data in the file
>>>>>            input = open(filename, 'r')
>>>>>            stuff=cPickle.load(input)
>>>>>            for line in stuff:
>>>>>                    #firstName=cPickle.load(input)
>>>>>                    #email=cPickle.load(input)
>>>>>                    #print repr (lastName).rjust(10), repr(firstName).rjust(20), repr
>>>>> (email).rjust(20)
>>>>>                    stuff=cPickle.load(input)
>>>>>                    print stuff
>>>>>                    print line
>>>>>            input.close()
>>>>>    if command=='exit' or command=='quit' : #NEVER forget the exit!!!
>>>>>            print 'Save changes? y for Yes, n for No'
>>>>>            commandSave=sys.stdin.readline()[:-1]
>>>>>            if commandSave =='y': #if the user wants to save
>>>>>                    output=open(filename, 'w')
>>>>>                    cPickle.dump(work,output)
>>>>>                    output.close()
>>>>>                    sys.exit(0)
>>>>>            if commandSave =='n': #no save
>>>>>                    input.close()
>>>>>                    sys.exit(0)
>>>>>    if command=='add': #adds an entity to the file
>>>>>            print 'Last name?'
>>>>>            lastName=sys.stdin.readline()[:-1]
>>>>>            print 'First name?'
>>>>>            firstName=sys.stdin.readline()[:-1]
>>>>>            print 'Email address?'
>>>>>            email=sys.stdin.readline()[:-1]
>>>>>            work = format%(lastName, firstName, email)
>>>>>            #output=open(filename, 'w')
>>>>>            #data=cPickle.load(output)
>>>>>            #data.append(work)
>>>>>            #output.close()
>>>>>            output=open(filename, 'a')
>>>>>            cPickle.dump(work,output)
>>>>>            output.close()
>>>>> 

>>>>> All help would be appreciated. I am new to Python and this seems to be
>>>>> quite a challenge for me.
>>>> Make sure you use modes "rb" and "wb" when you open the pickle files. If
>>>> you are running on Windows this can make a difference.
>>>> regards
>>>> Steve
>>>> --
>>>> Steve Holden +1 571 484 6266 +1 800 494 3119
>>>> Holden Web LLC http://www.holdenweb.com/
>>> I've tried both rb and wb as well as r and w, there appears to be no
>>> difference in the running of the code.
>> "cPickle.dump(work,output)" writes a string and
>> "stuff=cPickle.load(input)" just reads that string, so "for line in
>> stuff:" is iterating through the characters if the string. You need to
>> use cPickle.load() to read each string (line).
>
> Ok, so I just modified that section to:
>

> 	if command=='list': #lists the data in the file
> 		input = open(filename, 'r')
> 		stuff=cPickle.load(input)
> 		for line in stuff:

You're still iterating over the string.

> 			#firstName=cPickle.load(input)
> 			#email=cPickle.load(input)
> 			#print repr (lastName).rjust(10), repr(firstName).rjust(20), repr
> (email).rjust(20)
> 			stuff=cPickle.load(input)
> 			print stuff
> 
> 
> 		input.close()
> 

>
> And now it's printing it out ok, but then I get an EOFError at
> stuff=cPickle.load(onput) at line 45.
>
You can just keep reading until EOFError occurs, at which point you know
you've reached the end of the file:

input = open(filename, 'rb')
try:
while True:
stuff = cPickle.load(input)
print stuff
except EOFError:
pass
input.close()

MRAB

Thanks! All fixed!

mmcclaf