python help

**Glenton** · May 16 '10, 11:56 PM

Originally posted by manchesterboy

Hi all.
I'm currently doing coursework for my university, and im struggling with a bit of the code.

when i do the add_player statement, it doesn't want to edit the current ppp.txt file. When i list the players currently in the ppp.txt file its seems ok, its just adding a new player doesnt seem to work.

Code:

players=open("ppp.txt","r")


lis=[]


for line in players:
            line=line.strip()
            x=line.split(";")
         
            p=Person()
            p.surname=x[0]
            p.forename=x[1]
            p.email=x[2]
            p.phonenum=x[3]
            p.current_div=x[4]
            p.current_points=x[5]
            p.prev_div=x[6]
            p.prev_points=x[7]
            lis.append(p)
            for p in lis:
                
                print "%6s%12s%25s%14s%10s%10s%18s%15s"%(p.surname,p.forename,p.email,p.phonenum,p.current_div,p.current_points,
                p.prev_div,p.prev_points)

players.close()
            

        


def add_player(surname,forename,email,phone_num,current_div,current_points,prev_div,prev_points):  
    '''
    This function allows the user to add another player to the text file
        surname=surname of player
        forename=forename of the player 
        email=email of player
        phonenum=phonenum of player
        current_div= the current division for the player
        current_points=current points of the player
        prev_div=the previous division of the palyer
        prev_points=the previous points of the player
    '''
    
    lis.append([surname,forename,email,phone_num,current_div,current_points,prev_div,prev_points])

add_player("j","k","L","1","2","3","4","5")

Thanks is advance for your help, its much appreciated.

But your add function just appends it to the list called lis. You don't write it to the file at all!

You need to create a string from the data in the right format for your file (separated by semi-colons etc), and then write it to file. You could probably use the append mode, so something like this:

Code:

players=open("ppp.txt","a")
players.write(theStringOfYourData)
players.close()

**manchesterboy** · May 17 '10, 02:01 PM

Im new to the programming, so its taking me some time to get used to it
my ppp.txt file is written in the format:
krapa;peter;p.k ;565;1;2;3;55
for example.
so to add the next player onto the text file i would need to do the following:
players=open("p pp.txt","a") this allows me to append the file
the players.write(w ould i use the (x[0],x[1]...) file(this bit is confusing me)
then
players.close()
Its the players.write() bit. i am confused about, as it has not been covered in our lectures.
thanks for your help

**Nonemsludo** · May 17 '10, 03:21 PM

You say you already have the file open it for reading and writing or for writing only with "r+" or "w"

Code:

players=open("ppp.txt","r+"or "w")
players.write(theStringOfYourData)
players.close()

**Glenton** · May 18 '10, 12:23 AM

Originally posted by manchesterboy

Im new to the programming, so its taking me some time to get used to it
my ppp.txt file is written in the format:
krapa;peter;p.k ;565;1;2;3;55
for example.
so to add the next player onto the text file i would need to do the following:
players=open("p pp.txt","a") this allows me to append the file
the players.write(w ould i use the (x[0],x[1]...) file(this bit is confusing me)
then
players.close()
Its the players.write() bit. i am confused about, as it has not been covered in our lectures.
thanks for your help

The answer is "it depends". One of the things about python (and other dynamically typed languages if that's the right terminology) is that variables can be any type (string, integer, float, list, user-defined class, etc) and can flit from one to the other. When you write to a file it needs to be a string. So if your variable is a string already, then fine, otherwise you need to convert it.

You had this line:

Code:

add_player("j","k","L","1","2","3","4","5")

which suggests that all your variables are strings.

You could code it like this:

Code:

players.write(x[0]+";"+x[1]+";"+...)

or like this:

Code:

players.write("%s;%s;%s;..."%(x[0],x[1],...)

or, if the above looked like too much typing you could build up the string like this:

Code:

s=""
for item in x[:-1]:
    s+=item+";"
s+=x[-1]
players.write(s)

and there's probably more compact ways of doing this with list comprehensions.

**manchesterboy** · May 19 '10, 11:24 AM

thanks for the help!
my code now looks like thin

Code:

class Person(object):
    '''
    my list of squash players
    '''


players=open("ppp.txt","r")


lis=[]


for line in players:
            line=line.strip()
            x=line.split(";")
         
            p=Person()
            p.surname=x[0]
            p.forename=x[1]
            p.email=x[2]
            p.phonenum=x[3]
            p.current_div=x[4]
            p.current_points=x[5]
            p.prev_div=x[6]
            p.prev_points=x[7]
            lis.append(p)
            for p in lis:
                
                print "%6s%12s%25s%14s%10s%10s%18s%15s"%(p.surname,p.forename,p.email,p.phonenum,p.current_div,p.current_points,
                p.prev_div,p.prev_points)

players.close()
            

        




def add_player(surname,forename,email,phone_num,current_div,current_points,prev_div,prev_points):  
    '''
    This function allows the user to add another player to the text file
        surname=surname of player
        forename=forename of the player 
        email=email of player
        phonenum=phonenum of player
        current_div= the current division for the player
        current_points=current points of the player
        prev_div=the previous division of the palyer
        prev_points=the previous points of the player
    '''
    
    lis.append([surname,forename,email,phone_num,current_div,current_points,prev_div,prev_points])
    

players=open("ppp.txt","a")
add_player("franks","david","[email protected]","0445554","1","2","3","4")
players.write("%s;%s;%s;%s;%s;%s;%s;%s"%(x[0],x[1],x[2],x[3],x[4],x[5],x[6],x[7]))
players.close()

There now appears to be another problem:
The code doesn't write the new player into the text file, instead it seems to duplicate the player already in the text file, and just add it again.

I am confused as to why this is, as surely the add_player definition appends the list to add the player into it.
sorry if this problem seems trivial, i have never done programing before now, and its a steep learning curve
Thanks again

**Glenton** · May 19 '10, 11:59 AM

Originally posted by manchesterboy

thanks for the help!
my code now looks like thin

Code:

class Person(object):
    '''
    my list of squash players
    '''


players=open("ppp.txt","r")


lis=[]


for line in players:
            line=line.strip()
            x=line.split(";")
         
            p=Person()
            p.surname=x[0]
            p.forename=x[1]
            p.email=x[2]
            p.phonenum=x[3]
            p.current_div=x[4]
            p.current_points=x[5]
            p.prev_div=x[6]
            p.prev_points=x[7]
            lis.append(p)
            for p in lis:
                
                print "%6s%12s%25s%14s%10s%10s%18s%15s"%(p.surname,p.forename,p.email,p.phonenum,p.current_div,p.current_points,
                p.prev_div,p.prev_points)

players.close()
            

        




def add_player(surname,forename,email,phone_num,current_div,current_points,prev_div,prev_points):  
    '''
    This function allows the user to add another player to the text file
        surname=surname of player
        forename=forename of the player 
        email=email of player
        phonenum=phonenum of player
        current_div= the current division for the player
        current_points=current points of the player
        prev_div=the previous division of the palyer
        prev_points=the previous points of the player
    '''
    
    lis.append([surname,forename,email,phone_num,current_div,current_points,prev_div,prev_points])
    

players=open("ppp.txt","a")
add_player("franks","david","[email protected]","0445554","1","2","3","4")
players.write("%s;%s;%s;%s;%s;%s;%s;%s"%(x[0],x[1],x[2],x[3],x[4],x[5],x[6],x[7]))
players.close()

There now appears to be another problem:
The code doesn't write the new player into the text file, instead it seems to duplicate the player already in the text file, and just add it again.

I am confused as to why this is, as surely the add_player definition appends the list to add the player into it.
sorry if this problem seems trivial, i have never done programing before now, and its a steep learning curve
Thanks again

Hi

This is what your code does:
1. Defines a Person class;
2. Opens a file and creates a blank list (lis);
3. Reads the file line by line into a Person object via a temporary list x;
4. Appends each person object to lis (each time printing out the whole contents of lis);
5. Defines a function which appends to a local variable (also called lis) which hasn't been defined. I think python will pick it up anyway, but it's a dangerous way to live, IMHO!
6. Calls the function;
7. Adds the temporary x variable left over from the last step of 3 to the file.

You could use some structuring in your code! For example your Person class could have methods which returns the x variable or which takes a line from the file or returns a line to be written to the file or prints out a neat summary. It could also have the file name included which would allow you to read and write to the file.

But if you let us know what your grand vision is, perhaps we can help more with the structuring.

PS You're doing great! You're just going through the difficult transition from understanding the lines to understanding the structure. Or at least the first of those difficult transitions!

**manchesterboy** · May 19 '10, 12:08 PM

thanks for the reply.
My grand vision is as follows:
to make a text file of players, that then can then be edited, by adding/removing players etc
to get the text to print out the players, say in order of highest points, that can then be put into leagues etc.
to allows the user to maybe just look at one player in particular.
thats basically the programme i want to create.
Thanks

**Glenton** · May 19 '10, 02:18 PM

Okay. I suggest you get a text based one going first, and bolt the GUI on later. Much like you're trying to do, in fact.

You might want to think about one of the sql interfaces? But this is possibly too sophisticated for what you're trying to do. In fact there are probably several open source off-the-shelf things that achieve this kind of thing!

BUT...if you want to do it this way (and who wouldn't), we need to give some thought to structure. I'll try to have a think and post back. Let us know how it goes.

Oh, wait - this is for course work, not for real. Ah. That's different... I guess you'll have to come back with some questions!

**manchesterboy** · May 21 '10, 08:54 AM

The main point of this programme is to allow a use to edit a text file, , which contains players in it.
I have code sort of written, however we are told that using classes is much better. Basically, i want to transfrer this code

Code:

'''
code to maintain a list of squash players
'''
playersFin=open("players.txt","r")


def add_player(Surname,Forname,email,phone_num,current_division,points_current,prev_div,prev_points):
    '''
    Add a player to the bottom league
    '''
    players.append([Surname,Forname,email,phone_num,current_division,points_current,prev_div,prev_points])
    
def list_players():
    '''
    prints out the players in a list
    '''
    print "Surname   Forname        email                phone no.     current div   current points   previous div   previous points"
    for player in players:
            print "%6s%10s%25s%14s%10s%10s%18s%15s"%(player[0],player[1],player[2],player[3],player[4],player[5],player[6],player[7])

def read_players( filename ):
    '''
    Open a file in the format:
    Surname,Forname,email,phone_num,current_division,_points_current,prev_div,prev_points
    each line is then added to the players list
    The file is then closed
    '''
    f=open(filename,"r")
    for line in f:
        lis=line.split(";")
        Surname=lis[0]
        Forname=lis[1]
        email=lis[2]
        phone_num=lis[3]
        current_division=int(lis[4])
        points_current=int(lis[5])
        prev_div=int(lis[6])
        prev_points=int(lis[7])
        add_player(Surname,Forname,email,phone_num,current_division,points_current,prev_div,prev_points)
    f.close()
    
    
def write_players( filename ):
    '''
    Opens the file and writes out all the data
    '''
    f = open( filename , "w" )
    for p in players:
        f.write( "%s;%s;%s;%s;%d;%d;%d;%d\n" % (p[0],p[1],p[2],p[3],p[4],p[5],p[6],p[7]))
    f.close()
      
def delete_players(Surname):
    '''
    deletes a player from the list
    '''
   
    
    for j in range (0,len(players)):
	if players[j][0]==Surname:
		del players[j]
		break



def order_players():
    
players=[]
read_players( "players.txt" )
        
print

into a code the produces the same results, however is using classes. This is where i get horribly stuck!
Thanks

**Glenton** · May 21 '10, 09:05 AM

What have you tried so far? Broadly, what you're probably going to want to do is:

1. Define a Player class, which stores all the players details. In here you can have methods for manipulating the data. Eg a method to add the details in a list, a method to add the details in a line from the file, a method for printing the details, or returning the details in a line that will go into the file etc.

2. Define a Players or Database class (or whatever you're going to call it). Each object of this class is a Database (so you might anticipate only having one instance of it, but that's okay). Then initialise the Database with a file name. Store the file name as an instance variable, and maybe make a list of players.

I guess you could do it without the first class if you wanted.

Anyway, most of your methods just become class methods.

**manchesterboy** · May 21 '10, 09:16 AM

so something along these lines

Code:

playersFin=open("players.txt","r")


class Player(object):
    '''
    A squash player
    '''
    
    def __init__(self,surname,forename,email,phone,currdiv,currpoints,prevdiv,prevpoints):
        self.surname=surname
        self.forename=forename
        self.email=email
        self.phone=phone_number
        self.currdiv=currentddiv
        self.currpoints=currentpoints
        self.prevdiv=prevdiv
        self.prevpoints=prevpoints
 

    
    def add_player(self):
        '''
        adds player to the list
        '''
        players.append([self.surname,self.forename,self.email,self.phone,self.currdiv,
        self.currpoints,self.prevdiv,self.prevpoints])
    
        
class Database(object):




    



players=[]

however i am now back to struggling with the gritty code to make it all work smoothly!

**Glenton** · May 21 '10, 09:26 AM

So I was thinking more like this for the Player object

Code:

class Player(object):
    '''
    A squash player
    '''
 
    def __init__(self,surname=None,forename=None,email=None,phone=None,
currdiv=None,currpoints=None,prevdiv=None,prevpoints=None):
        if surname:
            self.surname=surname
            self.forename=forename
            self.email=email
            self.phone=phone_number
            self.currdiv=currentddiv
            self.currpoints=currentpoints
            self.prevdiv=prevdiv
            self.prevpoints=prevpoints
 
 
 
    def add_player(self,textstring):
        '''
        adds player to the list
        '''
        #Do whatever stripping and spliting to extract the relevant data from the 
        #textstring, and then set the players attributes to this
        self.surname=...

    def get_file_string(self):
        str=""
        if self.surname: str+=self.surname
        if self.forename: str+=self.forename
        etc...
        return str

    def get_list(self):
        return [self.surname,self.forename,...]

**manchesterboy** · May 21 '10, 09:42 AM

So, i have edited the code, and it makes sense, sort of.
However i need to utilise the text file that consists of the players that are already in the 'database'

Code:

class Player(object):
playersFin=open("players.txt","r")
    '''
    A squash player
    '''
 
    def __init__(self,surname=None,forename=None,email=None,phone=None,
currdiv=None,currpoints=None,prevdiv=None,prevpoints=None):
        if surname:
            self.surname=surname
            self.forename=forename
            self.email=email
            self.phone=phone_number
            self.currdiv=currentddiv
            self.currpoints=currentpoints
            self.prevdiv=prevdiv
            self.prevpoints=prevpoints
 
 
 
    def add_player(self,textstring):
        '''
        adds player to the list
        '''
        for line in players:
            line=line.strip()
            x=line.split(";")
            self.surname=x[0]
            self.forename=x[1]
            self.email=x[2]
            self.phone=x[3]
            self.currdiv=x[4]
            self.currpoints=x[5]
            self.prevdiv=x[6]
            self.prevpoints=x[7]
                
                
 
    def get_file_string(self):
        str=""
        if self.surname: str+=self.surname
        if self.forename: str+=self.forename
        if self.email: str+=self.email
        if self.phone: str+=self.phone
        if self.currdiv: str+=self.currdiv
        if self.currpoints: str+=self.currpoints
        if self.prevdiv: str+=self.prevdiv
        if self.prevpoints: str+=self.prevpoints
        return str
 
    def get_list(self):
        return [self.surname,self.forename,self.email,self.phone,self.currdiv,self.currpoints,
        self.prevdiv,self.prevpoints]

i have imported the text file playersFin
i now need to edit the code i have written, to allow me the add a player to the text file, then also allow me to delete a player, and if possible list the player according to their current point etc.
Thanks again for you help

**Glenton** · May 21 '10, 11:51 AM

Originally posted by manchesterboy

So, i have edited the code, and it makes sense, sort of.
However i need to utilise the text file that consists of the players that are already in the 'database'

Code:

class Player(object):
playersFin=open("players.txt","r")
    '''
    A squash player
    '''
 
    def __init__(self,surname=None,forename=None,email=None,phone=None,
currdiv=None,currpoints=None,prevdiv=None,prevpoints=None):
        if surname:
            self.surname=surname
            self.forename=forename
            self.email=email
            self.phone=phone_number
            self.currdiv=currentddiv
            self.currpoints=currentpoints
            self.prevdiv=prevdiv
            self.prevpoints=prevpoints
 
 
 
    def add_player(self,textstring):
        '''
        adds player to the list
        '''
        for line in players:
            line=line.strip()
            x=line.split(";")
            self.surname=x[0]
            self.forename=x[1]
            self.email=x[2]
            self.phone=x[3]
            self.currdiv=x[4]
            self.currpoints=x[5]
            self.prevdiv=x[6]
            self.prevpoints=x[7]
                
                
 
    def get_file_string(self):
        str=""
        if self.surname: str+=self.surname
        if self.forename: str+=self.forename
        if self.email: str+=self.email
        if self.phone: str+=self.phone
        if self.currdiv: str+=self.currdiv
        if self.currpoints: str+=self.currpoints
        if self.prevdiv: str+=self.prevdiv
        if self.prevpoints: str+=self.prevpoints
        return str
 
    def get_list(self):
        return [self.surname,self.forename,self.email,self.phone,self.currdiv,self.currpoints,
        self.prevdiv,self.prevpoints]

i have imported the text file playersFin
i now need to edit the code i have written, to allow me the add a player to the text file, then also allow me to delete a player, and if possible list the player according to their current point etc.
Thanks again for you help

This doesn't make sense to me. What is the Player object? A single player, or a database of players?

What I had intended was that it was a single player, and that another class structure would be used for the database (which will handle the file too). In the current situation you go through the file and over-write the single player with each new line. In the end you'll just have the last player - all the others will have been over-written.

My intention with the get_file_string method is that it will return the line for the player, so in this case it needs to have the semi-colons or whatever separator you're using between the bits.

Anyway, however you do it is up to you. My point is that you need to have it clear in your mind what is going to do what. And, if you want effective help, communicate that plan!

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