Can you use LINQ types and extension methods in IronPython?

Question

Is it possible to use the LINQ types and extension methods in IronPython?

If so how? And also is there often more pythonic to do the same thing?

Answer 1

IronPython 2.7 finally bridges this gap with the clr.ImportExtensions method which adds the extension methods from a namespace to the target types e.g.

>& 'C:\Program Files\IronPython 2.7\ipy.exe' IronPython 2.7 (2.7.0.40) on .NET 4.0.30319.225 Type "help", "copyright", "credits" or "license" for more information. >>> import clr >>> clr.AddReference("System.Core") >>> from System.Collections.Generic import List >>> dir (List) ['Add', 'AddRange', 'AsReadOnly', 'BinarySearch', 'Capacity', 'Clear', 'Contains', 'ConvertAll', 'CopyTo', 'Count', 'Enu merator', 'Equals', 'Exists', 'Find', 'FindAll', 'FindIndex', 'FindLast', 'FindLastIndex', 'ForEach', 'GetEnumerator', ' GetHashCode', 'GetRange', 'GetType', 'IndexOf', 'Insert', 'InsertRange', 'IsReadOnly', 'IsSynchronized', 'Item', 'LastIn dexOf', 'MemberwiseClone', 'ReferenceEquals', 'Remove', 'RemoveAll', 'RemoveAt', 'RemoveRange', 'Reverse', 'Sort', 'Sync Root', 'ToArray', 'ToString', 'TrimExcess', 'TrueForAll', '__add__', '__class__', '__contains__', '__delattr__', '__doc_ _', '__format__', '__getattribute__', '__getitem__', '__hash__', '__init__', '__iter__', '__len__', '__new__', '__reduce __', '__reduce_ex__', '__repr__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__'] >>> import System >>> clr.ImportExtensions(System.Linq) >>> dir (List) ['Add', 'AddRange', 'Aggregate', 'All', 'Any', 'AsEnumerable', 'AsParallel', 'AsQueryable', 'AsReadOnly', 'Average', 'Bi narySearch', 'Capacity', 'Cast', 'Clear', 'Concat', 'Contains', 'ConvertAll', 'CopyTo', 'Count', 'DefaultIfEmpty', 'Dist inct', 'ElementAt', 'ElementAtOrDefault', 'Enumerator', 'Equals', 'Except', 'Exists', 'Find', 'FindAll', 'FindIndex', 'F indLast', 'FindLastIndex', 'First', 'FirstOrDefault', 'ForEach', 'GetEnumerator', 'GetHashCode', 'GetRange', 'GetType', 'GroupBy', 'GroupJoin', 'IndexOf', 'Insert', 'InsertRange', 'Intersect', 'IsReadOnly', 'IsSynchronized', 'Item', 'Join',  'Last', 'LastIndexOf', 'LastOrDefault', 'LongCount', 'Max', 'MemberwiseClone', 'Min', 'OfType', 'OrderBy', 'OrderByDesc ending', 'ReferenceEquals', 'Remove', 'RemoveAll', 'RemoveAt', 'RemoveRange', 'Reverse', 'Select', 'SelectMany', 'Sequen ceEqual', 'Single', 'SingleOrDefault', 'Skip', 'SkipWhile', 'Sort', 'Sum', 'SyncRoot', 'Take', 'TakeWhile', 'ToArray', ' ToDictionary', 'ToList', 'ToLookup', 'ToString', 'TrimExcess', 'TrueForAll', 'Union', 'Where', 'Zip', '__add__', '__clas s__', '__contains__', '__delattr__', '__doc__', '__format__', '__getattribute__', '__getitem__', '__hash__', '__init__',  '__iter__', '__len__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setitem__', '__sizeof__' , '__str__', '__subclasshook__'] >>> 

which brings it into line with IronRuby 1.1's using_clr_extensions method.

Answer 2

Some of the things you'd do with LINQ can be done with list comprehensions:

[myFunc(i) for i in numbers if i > 3] 

Or you can use map, reduce, and filter:

map(myFunc, filter(lambda x: x > 3, numbers)) 

But list comprehensions are much more "Pythonic" than using the functional programming constructs. For reducing things, consider using "".join or sum. And you can check the truth value of entire iterables by using any and all.

Just remember these translations:

Select -> map Where -> filter Aggregate -> reduce 

And you'll be well on your way!