How do I most efficienty check the unique elements in a list?

Posted by alex on Stack Overflow See other posts from Stack Overflow or by alex
Published on 2010-04-02T22:43:29Z Indexed on 2010/04/02 22:53 UTC
Read the original article Hit count: 158

Filed under:

python

|

efficiency

|

list

|

dictionary

let's say I have a list

li = [{'q':'apple','code':'2B'},
      {'q':'orange','code':'2A'},
      {'q':'plum','code':'2A'}]

What is the most efficient way to return the count of unique "codes" in this list? In this case, the unique codes is 2, because only 2B and 2A are unique.

I could put everything in a list and compare, but is this really efficient?

© Stack Overflow or respective owner

Related posts about python

unmet dependencies in Ubuntu 12.04

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I tried today to install a dvb-card on my Ubuntu 12.04 (Linux blauhai-linux 3.2.0-25-generic #40-Ubuntu SMP Wed May 23 20:30:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux ). The installation failed with an error. After that, i tried to install python (it was already installed but i got this error): linux:~$… >>> More
How can I get sikuli-ide to work?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I installed sikuli-ide with sudo apt-get install sikuli-ide Everything was fine until I tried to start it from the terminal. I typed sikuli-ide But the only response I got was [info] locale: en_US The application was not started, furthermore there is no desktop file and sikuli-ide does not… >>> More
Getting PATH right for python after MacPorts install

as seen on Super User - Search for 'Super User'
I can't import some python libraries (PIL, psycopg2) that I just installed with MacPorts. I looked through these forums, and tried to adjust my PATH variable in $HOME/.bash_profile in order to fix this but it did not work. I added the location of PIL and psycopg2 to PATH. I know that Terminal is… >>> More
call python with system() in R to run a python script emulating the python console

as seen on Stack Overflow - Search for 'Stack Overflow'
I want to pass a chunk of Python code to Python in R with something like system('python ...'), and I'm wondering if there is an easy way to emulate the python console in this case. For example, suppose the code is "print 'hello world'", how can I get the output like this in R? >>> print… >>> More
Python - Calling a non python program from python?

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi, I am currently struggling to call a non python program from a python script. I have a ~1000 files that when passed through this C++ program will generate ~1000 outputs. Each output file must have a distinct name. The command I wish to run is of the form: program_name -input -output -o1 -o2… >>> More

Related posts about efficiency

iOS Efficiency File Saving Efficiency

as seen on Stack Overflow - Search for 'Stack Overflow'
I was working on my iOS app and my goal is to save a file that I am receiving from the internet bit by bit. My current setup is that I have a NSMutableData object and I add a bit of data to it as I receive my file. After the last "packet" is received, I write the NSData to a file and the process is… >>> More
Data Center Efficiency From the Ground Up

as seen on Internet.com - Search for 'Internet.com'
Hard-Core Hardware: It isn't often a data center gets to install the latest in servers, blades, storage and networking gear from Day One. Yet the Emerson data center in St. Louis, Missouri had just that opportunity. >>> More
Data Center Efficiency From the Ground Up

as seen on Internet.com - Search for 'Internet.com'
Hard-Core Hardware: It isn't often a data center gets to install the latest in servers, blades, storage and networking gear from Day One. Yet the Emerson data center in St. Louis, Missouri had just that opportunity. >>> More
Storage Energy Efficiency: Knowledge Is Power

as seen on Internet.com - Search for 'Internet.com'
When it comes to storage and data center energy costs, users aren't getting enough information, according to a recent report. >>> More
Meta on a Mac Delivers Efficiency Boost

as seen on Internet.com - Search for 'Internet.com'
Tip of the Trade: Tired of stretching your fingers to hit the ESC key on your Mac? There's a simple way to fix that. >>> More