New to Python: Do we have the concept of Hash in Python?

[A.M]

Hi,



I am new to Python, with C#/Java background



Is there any built-in Hash implementation in Python? I am looking for a
container that I can access to it's items by name. Something like this:



Print container["memeberNam e"]





I am asking this because I learned that DB-API in Python doesn't offer
access to cursor columns by name. The only option is access by index. I hope
that I've got it wrong!



I learned Ruby perfectly supports that.





Thank you,

Alan

[infidel]

Re: New to Python: Do we have the concept of Hash in Python?

> Is there any built-in Hash implementation in Python? I am looking for a[color=blue]
> container that I can access to it's items by name. Something like this:
>
> Print container["memeberNam e"][/color]

You obviously haven't read the tutorial, they're called "dictionari es"
in Python
[color=blue]
> I am asking this because I learned that DB-API in Python doesn't offer
> access to cursor columns by name. The only option is access by index. I hope
> that I've got it wrong![/color]

That's because the DB-API uses tuples to represent records.
[color=blue]
> I learned Ruby perfectly supports that.[/color]

Yay for Ruby.

[Brian Quinlan]

Re: New to Python: Do we have the concept of Hash in Python?

A.M wrote:[color=blue]
> Is there any built-in Hash implementation in Python? I am looking for a
> container that I can access to it's items by name. Something like this:
>
> Print container["memeberNam e"][/color]

d = {"memberName " : "some value"}
print d["memberName "]
[color=blue]
> I am asking this because I learned that DB-API in Python doesn't offer
> access to cursor columns by name. The only option is access by index. I hope
> that I've got it wrong!
>
> I learned Ruby perfectly supports that.[/color]

Python does not use column names by default because they are not
portable across database implementations . That being said, you can get
them easily, if you want. Look at the "descriptio n" attribute of your
cursor instance.

Cheers,
Brian

[Jeffrey Froman]

Re: New to Python: Do we have the concept of Hash in Python?

A.M wrote:
[color=blue]
> I am asking this because I learned that DB-API in Python doesn't offer
> access to cursor columns by name. The only option is access by index. I
> hope that I've got it wrong![/color]

While it's not part of the DB-API as far as I know, the MySQLdb package (and
perhaps other DB access modules as well, I don't know) provides
a "DictCursor " class that returns query results as a tuple of column-keyed
dictionaries (hashes, already demonstrated by Brian).


Jeffrey

[Fredrik Lundh]

Re: New to Python: Do we have the concept of Hash in Python?

"A.M" wrote:
[color=blue]
> I am new to Python, with C#/Java background[/color]

that's not really much of an excuse for not reading *any* Python tutorial before
you jump in...
[color=blue]
> I am asking this because I learned that DB-API in Python doesn't offer access to cursor columns by
> name. The only option is access by index. I hope that I've got it wrong![/color]

several people have already told you how to deal with this in Python. please see
the followups to your earlier post.
[color=blue]
> I learned Ruby perfectly supports that.[/color]

Ruby's DB interface, perhaps. Python's standard DB-API doesn't support this
by default, for portability and performance reasons. that doesn't mean that Python
don't have "hashes", just that the DB-API doesn't provide dictionary-style access
to columns.

see the followups to your earlier post for more details, and ways to handle this.

(a much better way to deal with this is of course to *name* the variables in your
select statements, so 1) the database engine can spot errors early on, and 2) it
won't have to fetch data that you don't really need).

</F>

[A.M]

Re: New to Python: Do we have the concept of Hash in Python?


"Fredrik Lundh" <fredrik@python ware.com> wrote in message
news:mailman.64 14.1149178232.2 7775.python-list@python.org ...[color=blue]
> "A.M" wrote:
>[color=green]
>> I am new to Python, with C#/Java background[/color]
>
> that's not really much of an excuse for not reading *any* Python tutorial
> before
> you jump in...[/color]

Hi Fredrik,

1st of all, I am really impressed by this Python community. Answers are
helpful and I am having excellent progress. I appreciate everybody's help.



This is my 1st day that I am seriously diving into Python and I have to
finish this application by the end of today. Maybe it wasn't a good idea to
choose the language that I don't know when I have to deliver my work in such
short time. I understand that my question might seems very trivial to you,
but please consider the fact that I am in time pressure and I cannot go
through a 400 book today. I promises I'll do that this weekend ;) Wish luck
for me!



Thank you for your post,

Alan

[gregarican]

Re: New to Python: Do we have the concept of Hash in Python?

Lemme see, starting *and* finishing a project in a language you've
never practically used before within a day's time? Sounds like a clip
from next season's opener of the TV show '24' to me.

I came from using Ruby about a year or so and even then it took a
couple of days of browsing through the Python docs and playing around
until I could consider myself somewhat useful. Coming from Java and C#
might make the departure a little steeper. Good luck!

A.M wrote:[color=blue]
> "Fredrik Lundh" <fredrik@python ware.com> wrote in message
> news:mailman.64 14.1149178232.2 7775.python-list@python.org ...[color=green]
> > "A.M" wrote:
> >[color=darkred]
> >> I am new to Python, with C#/Java background[/color]
> >
> > that's not really much of an excuse for not reading *any* Python tutorial
> > before
> > you jump in...[/color]
>
> Hi Fredrik,
>
> 1st of all, I am really impressed by this Python community. Answers are
> helpful and I am having excellent progress. I appreciate everybody's help.
>
>
>
> This is my 1st day that I am seriously diving into Python and I have to
> finish this application by the end of today. Maybe it wasn't a good idea to
> choose the language that I don't know when I have to deliver my work in such
> short time. I understand that my question might seems very trivial to you,
> but please consider the fact that I am in time pressure and I cannot go
> through a 400 book today. I promises I'll do that this weekend ;) Wish luck
> for me!
>
>
>
> Thank you for your post,
>
> Alan[/color]

[skip@pobox.com]

Re: New to Python: Do we have the concept of Hash in Python?


Alan> but please consider the fact that I am in time pressure and I
Alan> cannot go through a 400 book today.

The tutorial is online and not 400 pages long:

http://www.python.org/doc/current/tut/tut.html

It's got a pretty comprehensive table of contents, looking at which you
might jump quickly to Chapter 5, "Data Structures", and quickly eliminate
lists, sets and maybe tuples as possible synonyms for "hash" and investigate
Section 5.5, "Dictionari es" more closely. The first sentence of that
section should ring bells:

Another useful data type built into Python is the
dictionary. Dictionaries are sometimes found in other languages as
``associative memories'' or ``associative arrays''.

I suspect that was what Fredrik was thinking you might reasonably have done
before asking on the list. In addition, you could have probably answered
your own question faster by using the online documentation instead of
waiting for the Q&A round-trip to comp.lang.pytho n.

Skip

[Fredrik Lundh]

Re: New to Python: Do we have the concept of Hash in Python?

A.M wrote:
[color=blue]
> This is my 1st day that I am seriously diving into Python and I have to
> finish this application by the end of today. Maybe it wasn't a good idea to
> choose the language that I don't know when I have to deliver my work in such
> short time.[/color]

are your boss aware of this ?

</F>

[gregarican]

Re: New to Python: Do we have the concept of Hash in Python?

We have sort of a .... problem .... here .... uh .... yeah
(http://www.luminomagazine.com/2004.0...lumbergh1.jpg)...

Fredrik Lundh wrote:[color=blue]
> A.M wrote:
>[color=green]
> > This is my 1st day that I am seriously diving into Python and I have to
> > finish this application by the end of today. Maybe it wasn't a good idea to
> > choose the language that I don't know when I have to deliver my work in such
> > short time.[/color]
>
> are your boss aware of this ?
>
> </F>[/color]

[A.M]

Re: New to Python: Do we have the concept of Hash in Python?



"Fredrik Lundh" <fredrik@python ware.com> wrote in message
news:mailman.64 24.1149190330.2 7775.python-list@python.org ...[color=blue]
> A.M wrote:
>[color=green]
>> This is my 1st day that I am seriously diving into Python and I have to
>> finish this application by the end of today. Maybe it wasn't a good idea
>> to choose the language that I don't know when I have to deliver my work
>> in such short time.[/color]
>
> are your boss aware of this ?
>
> </F>
>[/color]

[color=blue]
> are your boss aware of this ?[/color]

What is wrong with *this*?
Yes, they are aware of *this*.
The application is not mission critical system. It is just a simple
reporting tool.

[A.M]

Re: New to Python: Do we have the concept of Hash in Python?


"Fredrik Lundh" <fredrik@python ware.com> wrote in message
news:mailman.64 24.1149190330.2 7775.python-list@python.org ...[color=blue]
> A.M wrote:
>[color=green]
>> This is my 1st day that I am seriously diving into Python and I have to
>> finish this application by the end of today. Maybe it wasn't a good idea
>> to choose the language that I don't know when I have to deliver my work
>> in such short time.[/color]
>
> are your boss aware of this ?
>
> </F>
>[/color]

[color=blue]
> are your boss aware of this ?[/color]

In fact my boss is quite impressed with my progress so far.



I am a little confused about the fact that you got frustrated with my posts
today. I am not asking for a big tutorial or

deepest philosophy behind the concepts. The answer to this post could be
just the word "Dictionary " which is 10 key stroke !

Does this hurt?

[John Machin]

Re: New to Python: Do we have the concept of Hash in Python?


A.M wrote:
[color=blue]
> The application is not mission critical system. It is just a simple
> reporting tool.[/color]

Famous last words.

[gregarican]

Re: New to Python: Do we have the concept of Hash in Python?

Dear A.M.,

The day is complete. My TPS reports still aren't on my desk. Either
with or without cover sheets. Not a good time to try to teach yourself
a new language. Please gather your belongings and move down to basement
storage C.

That'd be great,
Bill Lumberg

John Machin wrote:[color=blue]
> A.M wrote:
>[color=green]
> > The application is not mission critical system. It is just a simple
> > reporting tool.[/color]
>
> Famous last words.[/color]

[A.M]

Re: New to Python: Do we have the concept of Hash in Python?



Well the work is done now. I arrived home at 10:30 PM.



The application takes data from Oracle 10g stored procedures and renders
data to both HTML and CSV formats. The HTML reports have summary and
grouping sections and the HTML files are Excel friendly. The application is
modular and consists of reusable modules. The application is called every
night by scheduled task. The CSV and HTML files are being deployed to Apache
for internal employee access.



This isn't a complex and big system. Tomorrow, I'll add the email
functionality to the application and re-use it's components for more
reports.



Now that I finished the 1st part of the application, I have to admit that
choosing Python was an excellent decision. Python is an awesome programming
language with comprehensive library and great community support.



I am not that new to Python anymore.. I had a productive day. Thanks
everybody for help.





"gregarican " <greg.kujawa@gm ail.com> wrote in message
news:1149212030 .851030.257180@ c74g2000cwc.goo glegroups.com.. .[color=blue]
> Dear A.M.,
>
> The day is complete. My TPS reports still aren't on my desk. Either
> with or without cover sheets. Not a good time to try to teach yourself
> a new language. Please gather your belongings and move down to basement
> storage C.
>
> That'd be great,
> Bill Lumberg
>
> John Machin wrote:[color=green]
>> A.M wrote:
>>[color=darkred]
>> > The application is not mission critical system. It is just a simple
>> > reporting tool.[/color]
>>
>> Famous last words.[/color]
>[/color]