Correct way to detect sequence parameter?

Posted by noamtm on Stack Overflow See other posts from Stack Overflow or by noamtm
Published on 2008-11-20T13:52:44Z Indexed on 2010/03/30 20:33 UTC
Read the original article Hit count: 340

Filed under:

python

|

types

|

sequences

I want to write a function that accepts a parameter which can be either a sequence or a single value. The type of value is str, int, etc., but I don't want it to be restricted to a hardcoded list. In other words, I want to know if the parameter X is a sequence or something I have to convert to a sequence to avoid special-casing later. I could do

type(X) in (list, tuple)

but there may be other sequence types I'm not aware of, and no common base class.

-N.

Edit: See my "answer" below for why most of these answers don't help me. Maybe you have something better to suggest.

© 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 types

value types in the vm

as seen on Oracle Blogs - Search for 'Oracle Blogs'
value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} … >>> More
How can I get PowerShell Added-Types to use Added Types

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm working on a PoSh project that generates CSharp code, and then Add-Types it into memory. The new types use existing types in an on disk DLL, which is loaded via Add-Type. All is well and good untill I actualy try to invoke methods on the new types. Here's an example of what I'm doing: $PWD… >>> More
NDepend query methods/types in framework assembly being used by other assemblies/types

as seen on Stack Overflow - Search for 'Stack Overflow'
I am trying to determine which types or methods in a base framework assembly are being used by other assemblies in the application system. I cannot seem to find a straight-cut query to do that. What i have to do is first determine which assemblies are directly using the framework assembly, then manually… >>> More
Concrete Types or Interfaces for return types?

as seen on Stack Overflow - Search for 'Stack Overflow'
Today I came to a fundamental paradox of the object programming style, concrete types or interfaces. Whats the better election for a method's return type: a concrete type or an interface? In most cases, I tend to use concrete types as the return type for methods. because I believe that an concrete… >>> More
Using Scala structural types with abstract types

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm trying to define a structural type defining anything that has an "add" method (for instance, a java collection or a java map). Using this, I want to define a few higher order functions that operate on a certain collection object GenericTypes { type GenericCollection[T] = { def add(value: T):… >>> More