C# – List OrderBy Alphabetical Order

cgenericslambdalistsorting

I'm using C# on Framework 3.5. I'm looking to quickly sort a Generic List<T>. For the sake of this example, let's say I have a List of a Person type with a property of lastname. How would I sort this List using a lambda expression?

List<Person> people = PopulateList();
people.OrderBy(???? => ?????)

Best Answer

If you mean an in-place sort (i.e. the list is updated):

people.Sort((x, y) => string.Compare(x.LastName, y.LastName));

If you mean a new list:

var newList = people.OrderBy(x=>x.LastName).ToList(); // ToList optional

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if not a:
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Using the implicit booleanness of the empty list is quite pythonic.

Python – How to sort a list of dictionaries by a value of the dictionary

The sorted() function takes a key= parameter

newlist = sorted(list_to_be_sorted, key=lambda d: d['name'])

Alternatively, you can use operator.itemgetter instead of defining the function yourself

from operator import itemgetter
newlist = sorted(list_to_be_sorted, key=itemgetter('name'))

For completeness, add reverse=True to sort in descending order

newlist = sorted(list_to_be_sorted, key=itemgetter('name'), reverse=True)

Best Answer

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