In python, what does len(list) do?

Posted by nsharish on Stack Overflow See other posts from Stack Overflow or by nsharish
Published on 2010-03-08T07:18:36Z Indexed on 2010/03/08 7:21 UTC
Read the original article Hit count: 184

Filed under:

python

|

lists

My doubt is that if the len(list) calculates the length of the list everytime it is called or it returns the value of the builtin counter.
I have a context where i need to check the length of list everytime in a loop, like

listData = []
for value in ioread():
    if len(listData)>=25:
        processlistdata()
        clearlistdata()
    listData.append(value)

Should I check len(listData) every iteration, or can I have a counter for the length of the list.

© 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 lists

Global Address List, Multiple All Address Lists in CN=Address Lists Container

as seen on Server Fault - Search for 'Server Fault'
When my colleges (that was way before my time here) updated Exchange 2000 to 2003 a English All Address Lists appeared in addition to the German variant. The English All Address Lists have German titled GAL below it. This has just been a cosmetic problem for the last few years. Now as we are in the… >>> More
Lists inside lists don't validate with w3c?

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi everybody, I've got some lists inside lists to make some fancy drop-down menus. e.g <ul> <li>something <ul> <li>sub menu</li> </ul> </li> </ul> Problem is, w3c doesn't like it. Is there a way to make this validate… >>> More
Why are listener lists Lists?

as seen on Stack Overflow - Search for 'Stack Overflow'
Why are listener lists (e.g. in Java those that use addXxxListener() and removeXxxListener() to register and unregister listeners) called lists, and usually implemented as Lists? Wouldn't a Set be a better fit, since in the case of listeners there's No matter in which order they get called (although… >>> More
Updating Lists of Lists in Tapestry4 using textfields and a single submit button

as seen on Stack Overflow - Search for 'Stack Overflow'
In Tapestry 4 I am trying it iterate over a list of lists (technically a list of objects who have a list of strings as a data field). I am currently doing this by using 'nested' for components. (This is pseudo code) <span jwcid="Form"> <span jwcid="@For" source="ognl:Javaclass.TopLevelList"… >>> More
jQuery.each for lists and non-lists

as seen on Stack Overflow - Search for 'Stack Overflow'
I've a jQuery.each(data, foo), where data is either a string or a list of strings. I'd like to know if there's an existing utility function to convert the string to a list, or otherwise perform foo on just the string. So instead of the easy route: if (!$.isArray(data)) { foo(0, data); // can't… >>> More