473,773 Members | 2,315 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Reading a CSV file into a list of dictionaries

RFQ
Hi, I'm struggling here to do the following with any success:

I have a comma delimited file where each line in the file is something
like:

PNumber,3056,Co ntractor,XYZ Contracting,Arc hitect,ABC Architects,...

So each line is intended to be: key1,value1,key 2,value2,key3,v alue3...
and each line is to be variable in length (although it will have to be
an even number of records so that each key has a value).

I want to read in this csv file and parse it into a list of
dictionaries. So each record in the list is a dictionary:

{"PNumber":"305 6","Contractor" :"XYZ Contracting", ... }

I have no problem reading in the CSV file to a list and splitting each
line in the file into its comma separated values. But I can't figure
out how to parse each resulting list into a dictionary.

Any help on this?

Jul 19 '05 #1
7 7659
RFQ wrote:
Hi, I'm struggling here to do the following with any success:

I have a comma delimited file where each line in the file is something
like:

PNumber,3056,Co ntractor,XYZ Contracting,Arc hitect,ABC Architects,...

So each line is intended to be: key1,value1,key 2,value2,key3,v alue3...
and each line is to be variable in length (although it will have to be
an even number of records so that each key has a value).

I want to read in this csv file and parse it into a list of
dictionaries. So each record in the list is a dictionary:

{"PNumber":"305 6","Contractor" :"XYZ Contracting", ... }

I have no problem reading in the CSV file to a list and splitting each
line in the file into its comma separated values. But I can't figure
out how to parse each resulting list into a dictionary.


First, don't process the CSV stuff yourself. Use the csv module.

In [9]:import csv

In [10]:f = open('foo.csv')

In [11]:cr = csv.reader(f)

In [12]:for row in cr:
....: print dict(zip(row[::2], row[1::2]))
....:
{'Architect': 'ABC Architects', 'PNumber': '3056', 'Contractor': 'XYZ
Contracting'}
{'Architect': 'ABC Architects', 'PNumber': '3056', 'Contractor': 'XYZ
Contracting'}
[etc.]

--
Robert Kern
rk***@ucsd.edu

"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter

Jul 19 '05 #2
RFQ wrote:
I have a comma delimited file where each line in the file is something
like:

PNumber,3056,Co ntractor,XYZ Contracting,Arc hitect,ABC Architects,...

So each line is intended to be: key1,value1,key 2,value2,key3,v alue3...
and each line is to be variable in length (although it will have to be
an even number of records so that each key has a value).

I want to read in this csv file and parse it into a list of
dictionaries. So each record in the list is a dictionary:

{"PNumber":"305 6","Contractor" :"XYZ Contracting", ... }

row ['PNumber', '3056', 'Contractor', 'XYZ Contracting', 'Architect', 'ABC'] dict(zip(row[::2], row[1::2])) {'Architect': 'ABC', 'PNumber': '3056', 'Contractor': 'XYZ Contracting'}

A bit more elegant:
irow = iter(row)
dict(zip(irow, irow))

{'Architect': 'ABC', 'PNumber': '3056', 'Contractor': 'XYZ Contracting'}

Peter

Jul 19 '05 #3
Sounds like you want to use the ConfigObject module.

http://www.voidspace.org.uk/python/m...html#configobj

-dave

"RFQ" <rf******@gmail .com> wrote in message
news:11******** *************@f 14g2000cwb.goog legroups.com...
Hi, I'm struggling here to do the following with any success:

I have a comma delimited file where each line in the file is something
like:

PNumber,3056,Co ntractor,XYZ Contracting,Arc hitect,ABC Architects,...

So each line is intended to be: key1,value1,key 2,value2,key3,v alue3...
and each line is to be variable in length (although it will have to be
an even number of records so that each key has a value).

I want to read in this csv file and parse it into a list of
dictionaries. So each record in the list is a dictionary:

{"PNumber":"305 6","Contractor" :"XYZ Contracting", ... }

I have no problem reading in the CSV file to a list and splitting each
line in the file into its comma separated values. But I can't figure
out how to parse each resulting list into a dictionary.

Any help on this?

--
http://mail.python.org/mailman/listinfo/python-list


Jul 19 '05 #4
RFQ wrote:
Hi, I'm struggling here to do the following with any success:

I have a comma delimited file where each line in the file is something
like:

PNumber,3056,Co ntractor,XYZ Contracting,Arc hitect,ABC Architects,...
This is NOT a CSV file. A CSV file would be :

PNumber,Contrac tor,Architect,. ..
2056,XYZ Contracting,ABC Architects,...

Then, you could use the built-in CSV module of recent python versions.

So each line is intended to be: key1,value1,key 2,value2,key3,v alue3...
and each line is to be variable in length (although it will have to be
an even number of records so that each key has a value).

I want to read in this csv file and parse it into a list of
dictionaries. So each record in the list is a dictionary:

{"PNumber":"305 6","Contractor" :"XYZ Contracting", ... }

I have no problem reading in the CSV file to a list and splitting each
line in the file into its comma separated values. But I can't figure
out how to parse each resulting list into a dictionary.

Any help on this?


By,

Jul 19 '05 #5
Laurent RAHUEL wrote:
RFQ wrote:

Hi, I'm struggling here to do the following with any success:

I have a comma delimited file where each line in the file is something
like:

PNumber,3056, Contractor,XYZ Contracting,Arc hitect,ABC Architects,...

This is NOT a CSV file. A CSV file would be :

PNumber,Contrac tor,Architect,. ..
2056,XYZ Contracting,ABC Architects,...


CSV is an acronym for "Comma-Separated Values". It does not imply
anything about the contents of the fields. The OP's file *is* a CSV
file. Yes, the contents do represent an unusual application of the CSV
format -- however a bus full of parcels instead of people is still a bus.
Then, you could use the built-in CSV module of recent python versions.


Python is a case-sensitive language. The name of the module is "csv".
The OP could use the csv module with his data.
Jul 19 '05 #6
John Machin wrote:
Laurent RAHUEL wrote:
RFQ wrote:

Hi, I'm struggling here to do the following with any success:

I have a comma delimited file where each line in the file is something
like:

PNumber,3056 ,Contractor,XYZ Contracting,Arc hitect,ABC Architects,...

This is NOT a CSV file. A CSV file would be :

PNumber,Contrac tor,Architect,. ..
2056,XYZ Contracting,ABC Architects,...


CSV is an acronym for "Comma-Separated Values". It does not imply
anything about the contents of the fields. The OP's file *is* a CSV
file. Yes, the contents do represent an unusual application of the CSV
format -- however a bus full of parcels instead of people is still a bus.


I thought you knew the number of cols and what you should expect in each.
Then it sounded pretty easy to build a list of dictionaries. If you don't
know what you're supposed to find in your file and how this file is
structured I guess you don't know what you are doing.
Then, you could use the built-in CSV module of recent python versions.


Python is a case-sensitive language. The name of the module is "csv".
The OP could use the csv module with his data.


Damn, that's why I always see those annoynig import errors.

I just wanted to help, maybe you're to much case-sensitive.

Regards,

Laurent.

Jul 19 '05 #7
Laurent RAHUEL wrote:
I thought you knew the number of cols and what you should expect in each.
Then it sounded pretty easy to build a list of dictionaries. If you don't
know what you're supposed to find in your file and how this file is
structured I guess you don't know what you are doing.


That's not what the OP asked about.

[RFQ:]
"""So each line is intended to be: key1,value1,key 2,value2,key3,v alue3...
and each line is to be variable in length (although it will have to be
an even number of records so that each key has a value)."""

The rows are not all of the same format. The OP *does* know the
structure, and he (?) *does* know what he's doing. It's just not the
structure usually used in CSV files.

The csv module, of course, still reads these rows just fine; they just
need to be processed a bit to get the correct dictionaries.

--
Robert Kern
rk***@ucsd.edu

"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter

Jul 19 '05 #8

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

10
6961
by: Luis P. Mendes | last post by:
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, my program builds a dictionary that I would like to save in a file. My question is what are the simple ways to do it? The first solution I've thought of is to transform the dictionary in a
7
2574
by: Philipp H. Mohr | last post by:
Hello, I would like to store multiple dictionaries in a file, if possible one per line. My code currently produces a new dictionary every iteration and passes it on to another peace of code. In order to be able to re-run some experiments at a later date I would like to store every dictionary in the same file. I looked at pickel, but that seems to require a whole file for each dictionary.
6
2027
by: Angelic Devil | last post by:
I'm building a file parser but I have a problem I'm not sure how to solve. The files this will parse have the potential to be huge (multiple GBs). There are distinct sections of the file that I want to read into separate dictionaries to perform different operations on. Each section has specific begin and end statements like the following: KEYWORD .. ..
90
10820
by: Christoph Zwerschke | last post by:
Ok, the answer is easy: For historical reasons - built-in sets exist only since Python 2.4. Anyway, I was thinking about whether it would be possible and desirable to change the old behavior in future Python versions and let dict.keys() and dict.values() both return sets instead of lists. If d is a dict, code like: for x in d.keys():
2
2629
by: David Pratt | last post by:
Hi. I like working with lists of dictionaries since order is preserved in a list when I want order and the dictionaries make it explicit what I have got inside them. I find this combination very useful for storing constants especially. Generally I find myself either needing to retrieve the values of constants in an iterative way (as in my contrived example below). Perhaps even more frequent is given one value is to look up the matching...
9
1632
by: rbt | last post by:
What's a good way to write a dictionary out to a file so that it can be easily read back into a dict later? I've used realines() to read text files into lists... how can I do the same thing with dicts? Here's some sample output that I'd like to write to file and then read back into a dict: {'.\\sync_pics.py': 1135900993, '.\\file_history.txt': 1135900994, '.\\New Text Document.txt': 1135900552}
4
2491
by: techiepundit | last post by:
I'm a Python newbie who just started learning the language a few weeks ago. So these are beginner questions. I have a list of sockets that I use for select.select calls like this: ReadList,WriteList,EventList = select.select(self.SocketList,,,3) In parallel with that list of sockets I want something that is like a list of socket,PacketFragment pairs. I need this because I could do recv and get part of a sent packet. I want to loop...
3
3555
by: shigehiro | last post by:
Hi all, Further to my 'list of dictionaries' question yesterday, I would to ask how to write data to csv file format using 'list of dictionaries' as a source: data to be written to .csv file: dictList = so the csv file would look something like: Michael,Kirk,224567 Linda,Matthew,123456
0
128
by: Jon Bowlas | last post by:
Many thanks for all your reponses, much appreciated. I'll get back to you on which is the best for me. BTW - yes John thats exactly what I wanted. Cheers Jon
0
9621
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
0
9454
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
10264
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
1
10039
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
8937
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
0
6717
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5355
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
1
4012
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
2
3610
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.