public class Abbreviation
{
public string ShortName { get; set; }
public string LongName { get; set; }
}
I have a list of Abbreviation objects like this:
List abbreviations = new List();
abbreviations.add(new Abbreviation() {ShortName = "exp.", LongName = "expression"});
abbreviations.add(new Abbreviation() {ShortName = "para.", LongName = "paragraph"});
abbreviations.add(new Abbreviation() {ShortName = "ans.", LongName = "answer"});
string test = "this is a test exp. in a para. contains ans. for a question";
string result = test.Replace("exp.", "expression")
...
I expect the result to be:
"this is a test expression in a paragraph contains answer for a question"
Currently I am doing:
foreach (Abbreviation abbreviation in abbreviations)
{
test = test.Replace(abbreviation.ShortName, abbreviation.LongName);
}
result = test;
Wondering if there is a better way using a combination of Linq and Regex.
If you really wanted to shorten your code, you could use the ForEach extension method on the List:
abbreviations.ForEach(x=> test=test.Replace(x.ShortName, x.LongName));
You could use the ForEach method. Also, a StringBuilder should make the operations on your string more efficient:
var test = new StringBuilder("this is a test exp. in a para. contains ans. for a question");
abbreviations.ForEach(abb => test = test.Replace(abb.ShortName, abb.LongName));
return test.ToString();
Try this one
TestList.ForEach(x => x.TestType.Replace("", "DataNotAvailable"));
or the one below
foreach (TestModel item in TestList.Where(x => x.ID == ""))
{
item.ID = "NoDataAvailable";
}
Related
i have a single textbox named Keywords.
User can enter multiple strings for search.
How this is possible in mvc3?
I am using nhibernate as ORM.
Can i create criteria for this?
Edited Scenario
I have partial view to search job based on following values:
Keywords(multiple strings), Industry(cascading dropdown with functional area )//working well ,FunctionalArea//working well
Loaction(multiple locations), Experience//working well
In Controller i am retrieving these values from form collection.
What datatype should i use for keywords and location (string or string[] )?
public ActionResult SearchResult(FormCollection formCollection)
{
IList<Jobs> JobsSearchResultList = new List<Jobs>();
//string[] keywords = null;
string location = null;
int? industry = 0;
int? functionaArea = 0;
int? experience = 0;
string keywords = null;
if (formCollection["txtKeyword"] != "")
{
keywords = formCollection["txtKeyword"];
}
//if (formCollection["txtKeyword"] != "")
//{
// keywordAry = formCollection["txtKeyword"].Split(' ');
// foreach (string keyword in keywordAry)
// {
// string value = keyword;
// }
//}
......retrieving other values from formcollection
....
//Now passing these values to Service method where i have criteria for job search
JobsSearchResultList = oEasyJobsService.GetJobsOnSearchExists(keywords,industry,functionaArea,location,experience);
return View(JobsSearchResultList);
}
In Services i have done like:
public IList<EASYJobs> GetJobsOnSearchExists(string keywords, int? industryId, int? functionalAreaId, string location, int? experience)
{
IList<JobLocation> locationlist = new List<JobLocation>();
IList<Jobs> JobsList = null;
var disjunction = Expression.Disjunction();
ICriteria query = session.CreateCriteria(typeof(Jobs), "EJobs");
if (keywords != null)
{
foreach (string keyword in keywords)
{
string pattern = String.Format("%{0}%", keyword);
disjunction
.Add(Restrictions.InsensitiveLike("Jobs.keywords", pattern,MatchMode.Anywhere))
.Add(Restrictions.InsensitiveLike("YJobs.PostTitle",pattern,MatchMode.Anywhere));
}
query.Add(disjunction)
.Add(Expression.Eq("EASYJobs.Industry.IndustryId", industryId))
.Add(Expression.Eq("Jobs.FunctionalArea.FunctionalAreaId", functionalAreaId))
.Add(Expression.Eq("Jobs.RequiredExperience", experience)));
}
else
{..
}
JobsList = criteria.List<Jobs>();
}
Problems i am facing are:
In controller if i use string[],then Split(',') does not split the string with specified separator.It passes string as it is to Service.
2.In services i am trying to replace string with %{0}% ,strings with spaces are replaced/concat() here with given delimeter.
But the problem here is It always return the whole job list means not giving the required output.
Pleas help ...
As long as you have a delimiter you can break the input into pieces on you should be able to create an or expression with the parts. You can use a disjunction to combine an arbitrary number of criteria using OR's.
var criteria = session.CreateCriteria<TestObject>();
Junction disjunction = Restrictions.Disjunction();
var input = "key words";
foreach (var keyword in input.Split(" "))
{
ICriterion criterion = Restrictions.Eq("PropertyName", keyword);
disjunction.Add(criterion);
}
criteria.Add(disjunction);
Multiple keywords with special characters or extra spaces are replaced with single space with Regex expressions.
And then keywords are separated with Split("").
Its working as required....
if (!string.IsNullOrEmpty(keywords))
{
keywords = keywords.Trim();
keywords = System.Text.RegularExpressions.Regex.Replace(keywords, #"[^0-9a-zA-Z\._\s]", " ");
keywords = System.Text.RegularExpressions.Regex.Replace(keywords, #"[\s]+", " ");
if (keywords.IndexOf(" ") > 0)
{
string[] arr = keywords.Split(" ".ToCharArray());
for (int i = 0; i < arr.Length; i++)
{
if (!string.IsNullOrEmpty(arr[i]))
{
criteria.Add(Restrictions.Disjunction()
.Add(Expression.Like("EASYJobs.keywords", arr[i], MatchMode.Anywhere)));
}
}
}
else
{
criteria.Add(Restrictions.Disjunction()
.Add(Expression.Like("EASYJobs.keywords", keywords, MatchMode.Anywhere)));
}
}
I have a sample CSV file as follows
1,A
2,B
3,C
Code:
var query = File.ReadAllLines("test.txt")
.Select(record => record.Split(','))
.Select(tokens => new { clearNum = tokens[0], MPID = tokens[1] });
foreach (var item in query)
{
Console.WriteLine("{0}, {1}", item.clearNum, item.MPID);
}
I am able to print the items.
I need to send the output of LINQ query to LIST
public class icSASList
{
public string ClearNum { get; set; }
public string MPID { get; set; }
}
List clearList = new List;
After considering the accepted answer, I'd like to suggest a solution that requires less object initializations. If the list is large, this will make a difference.
var query = File.ReadAllLines("test.txt")
.Select(record => record.Split(','))
.Select(tokens => new icSASList(){ ClearNum = tokens[0], MPID = tokens[1] });
var clearList = query.ToList();
Oh, yeah, using record.Split(',') is naive - it's normally allowed to have commas in " (quoted) fields, which will break your program. Better use something like http://www.filehelpers.com/.
I've not tried compiling it but I think you want something like this?
var clearList = query.Select(x=>new icSASList(){ClearNum = x.clearNum, MPID = x.MPID}).ToList();
I have a collection of CLR objects. The class definition for the object has three properties: FirstName, LastName, BirthDate.
I have a string that reflects the name of the property the collection should be sorted by. In addition, I have a sorting direction. How do I dynamically apply this sorting information to my collection? Please note that sorting could be multi-layer, so for instance I could sort by LastName, and then by FirstName.
Currently, I'm trying the following without any luck:
var results = myCollection.OrderBy(sortProperty);
However, I'm getting a message that says:
... does not contain a defintion for 'OrderBy' and the best extension method overload ... has some invalid arguments.
Okay, my argument with SLaks in his comments has compelled me to come up with an answer :)
I'm assuming that you only need to support LINQ to Objects. Here's some code which needs significant amounts of validation adding, but does work:
// We want the overload which doesn't take an EqualityComparer.
private static MethodInfo OrderByMethod = typeof(Enumerable)
.GetMethods(BindingFlags.Public | BindingFlags.Static)
.Where(method => method.Name == "OrderBy"
&& method.GetParameters().Length == 2)
.Single();
public static IOrderedEnumerable<TSource> OrderByProperty<TSource>(
this IEnumerable<TSource> source,
string propertyName)
{
// TODO: Lots of validation :)
PropertyInfo property = typeof(TSource).GetProperty(propertyName);
MethodInfo getter = property.GetGetMethod();
Type propType = property.PropertyType;
Type funcType = typeof(Func<,>).MakeGenericType(typeof(TSource), propType);
Delegate func = Delegate.CreateDelegate(funcType, getter);
MethodInfo constructedMethod = OrderByMethod.MakeGenericMethod(
typeof(TSource), propType);
return (IOrderedEnumerable<TSource>) constructedMethod.Invoke(null,
new object[] { source, func });
}
Test code:
string[] foo = new string[] { "Jon", "Holly", "Tom", "William", "Robin" };
foreach (string x in foo.OrderByProperty("Length"))
{
Console.WriteLine(x);
}
Output:
Jon
Tom
Holly
Robin
William
It even returns an IOrderedEnumerable<TSource> so you can chain ThenBy clauses on as normal :)
You need to build an Expression Tree and pass it to OrderBy.
It would look something like this:
var param = Expression.Parameter(typeof(MyClass));
var expression = Expression.Lambda<Func<MyClass, PropertyType>>(
Expression.Property(param, sortProperty),
param
);
Alternatively, you can use Dynamic LINQ, which will allow your code to work as-is.
protected void sort_grd(object sender, GridViewSortEventArgs e)
{
if (Convert.ToBoolean(ViewState["order"]) == true)
{
ViewState["order"] = false;
}
else
{
ViewState["order"] = true;
}
ViewState["SortExp"] = e.SortExpression;
dataBind(Convert.ToBoolean(ViewState["order"]), e.SortExpression);
}
public void dataBind(bool ord, string SortExp)
{
var db = new DataClasses1DataContext(); //linq to sql class
var Name = from Ban in db.tbl_Names.AsEnumerable()
select new
{
First_Name = Ban.Banner_Name,
Last_Name = Ban.Banner_Project
};
if (ord)
{
Name = BannerName.OrderBy(q => q.GetType().GetProperty(SortExp).GetValue(q, null));
}
else
{
Name = BannerName.OrderByDescending(q => q.GetType().GetProperty(SortExp).GetValue(q, null));
}
grdSelectColumn.DataSource = Name ;
grdSelectColumn.DataBind();
}
you can do this with Linq
var results = from c in myCollection
orderby c.SortProperty
select c;
For dynamic sorting you could evaluate the string i.e. something like
List<MyObject> foo = new List<MyObject>();
string sortProperty = "LastName";
var result = foo.OrderBy(x =>
{
if (sortProperty == "LastName")
return x.LastName;
else
return x.FirstName;
});
For a more generic solution see this SO thread: Strongly typed dynamic Linq sorting
For this sort of dynamic work I've been using the Dynamic LINQ library which makes this sort of thing easy:
http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx
http://msdn2.microsoft.com/en-us/vcsharp/bb894665.aspx
You can copy paste the method I post in that answer, and change the signature/method names:
How to make the position of a LINQ Query SELECT variable
You can actually use your original line of code
var results = myCollection.OrderBy(sortProperty);
simply by using the System.Linq.Dynamic library.
If you get a compiler error (something like cannot convert from or does not contain a definition...) you may have to do it like this:
var results = myCollection.AsQueryable().OrderBy(sortProperty);
No need for any expression trees or data binding.
You will need to use reflection to get the PropertyInfo, and then use that to build an expression tree. Something like this:
var entityType = typeof(TEntity);
var prop = entityType.GetProperty(sortProperty);
var param = Expression.Parameter(entityType, "x");
var access = Expression.Lambda(Expression.MakeMemberAccess(param, prop), param);
var ordered = (IOrderedQueryable<TEntity>) Queryable.OrderBy(
myCollection,
(dynamic) access);
I want to do this:
var orderBy = "Nome, Cognome desc";
var timb = time.Timbratures.Include("Anagrafica_Dipendente")
.Where(p => p.CodDipendente == 1);
if(orderBy != "")
timb = timb.OrderBy(orderBy);
Is there an OrderBy overload available that accepts a string parameter?
If you are using plain LINQ-to-objects and don't want to take a dependency on an external library it is not hard to achieve what you want.
The OrderBy() clause accepts a Func<TSource, TKey> that gets a sort key from a source element. You can define the function outside the OrderBy() clause:
Func<Item, Object> orderByFunc = null;
You can then assign it to different values depending on the sort criteria:
if (sortOrder == SortOrder.SortByName)
orderByFunc = item => item.Name;
else if (sortOrder == SortOrder.SortByRank)
orderByFunc = item => item.Rank;
Then you can sort:
var sortedItems = items.OrderBy(orderByFunc);
This example assumes that the source type is Item that have properties Name and Rank.
Note that in this example TKey is Object to not constrain the property types that can be sorted on. If the func returns a value type (like Int32) it will get boxed when sorting and that is somewhat inefficient. If you can constrain TKey to a specific value type you can work around this problem.
Absolutely. You can use the LINQ Dynamic Query Library, found on Scott Guthrie's blog. There's also an updated version available on CodePlex.
It lets you create OrderBy clauses, Where clauses, and just about everything else by passing in string parameters. It works great for creating generic code for sorting/filtering grids, etc.
var result = data
.Where(/* ... */)
.Select(/* ... */)
.OrderBy("Foo asc");
var query = DbContext.Data
.Where(/* ... */)
.Select(/* ... */)
.OrderBy("Foo ascending");
Another solution from codeConcussion (https://stackoverflow.com/a/7265394/2793768)
var param = "Address";
var pi = typeof(Student).GetProperty(param);
var orderByAddress = items.OrderBy(x => pi.GetValue(x, null));
The simplest & the best solution:
mylist.OrderBy(s => s.GetType().GetProperty("PropertyName").GetValue(s));
You don't need an external library for this. The below code works for LINQ to SQL/entities.
/// <summary>
/// Sorts the elements of a sequence according to a key and the sort order.
/// </summary>
/// <typeparam name="TSource">The type of the elements of <paramref name="query" />.</typeparam>
/// <param name="query">A sequence of values to order.</param>
/// <param name="key">Name of the property of <see cref="TSource"/> by which to sort the elements.</param>
/// <param name="ascending">True for ascending order, false for descending order.</param>
/// <returns>An <see cref="T:System.Linq.IOrderedQueryable`1" /> whose elements are sorted according to a key and sort order.</returns>
public static IQueryable<TSource> OrderBy<TSource>(this IQueryable<TSource> query, string key, bool ascending = true)
{
if (string.IsNullOrWhiteSpace(key))
{
return query;
}
var lambda = (dynamic)CreateExpression(typeof(TSource), key);
return ascending
? Queryable.OrderBy(query, lambda)
: Queryable.OrderByDescending(query, lambda);
}
private static LambdaExpression CreateExpression(Type type, string propertyName)
{
var param = Expression.Parameter(type, "x");
Expression body = param;
foreach (var member in propertyName.Split('.'))
{
body = Expression.PropertyOrField(body, member);
}
return Expression.Lambda(body, param);
}
(CreateExpression copied from https://stackoverflow.com/a/16208620/111438)
I did so:
using System.Linq.Expressions;
namespace System.Linq
{
public static class LinqExtensions
{
public static IOrderedQueryable<TSource> OrderBy<TSource>(this IQueryable<TSource> source, string field, string dir = "asc")
{
// parametro => expressão
var parametro = Expression.Parameter(typeof(TSource), "r");
var expressao = Expression.Property(parametro, field);
var lambda = Expression.Lambda(expressao, parametro); // r => r.AlgumaCoisa
var tipo = typeof(TSource).GetProperty(field).PropertyType;
var nome = "OrderBy";
if (string.Equals(dir, "desc", StringComparison.InvariantCultureIgnoreCase))
{
nome = "OrderByDescending";
}
var metodo = typeof(Queryable).GetMethods().First(m => m.Name == nome && m.GetParameters().Length == 2);
var metodoGenerico = metodo.MakeGenericMethod(new[] { typeof(TSource), tipo });
return metodoGenerico.Invoke(source, new object[] { source, lambda }) as IOrderedQueryable<TSource>;
}
public static IOrderedQueryable<TSource> ThenBy<TSource>(this IOrderedQueryable<TSource> source, string field, string dir = "asc")
{
var parametro = Expression.Parameter(typeof(TSource), "r");
var expressao = Expression.Property(parametro, field);
var lambda = Expression.Lambda<Func<TSource, string>>(expressao, parametro); // r => r.AlgumaCoisa
var tipo = typeof(TSource).GetProperty(field).PropertyType;
var nome = "ThenBy";
if (string.Equals(dir, "desc", StringComparison.InvariantCultureIgnoreCase))
{
nome = "ThenByDescending";
}
var metodo = typeof(Queryable).GetMethods().First(m => m.Name == nome && m.GetParameters().Length == 2);
var metodoGenerico = metodo.MakeGenericMethod(new[] { typeof(TSource), tipo });
return metodoGenerico.Invoke(source, new object[] { source, lambda }) as IOrderedQueryable<TSource>;
}
}
}
Use :
example.OrderBy("Nome", "desc").ThenBy("other")
Work like:
example.OrderByDescending(r => r.Nome).ThenBy(r => r.other)
Look at this blog here. It describes a way to do this, by defining an EntitySorter<T>.
It allows you to pass in an IEntitySorter<T> into your service methods and use it like this:
public static Person[] GetAllPersons(IEntitySorter<Person> sorter)
{
using (var db = ContextFactory.CreateContext())
{
IOrderedQueryable<Person> sortedList = sorter.Sort(db.Persons);
return sortedList.ToArray();
}
}
And you can create an EntitiySorter like this:
IEntitySorter<Person> sorter = EntitySorter<Person>
.OrderBy(p => p.Name)
.ThenByDescending(p => p.Id);
Or like this:
var sorter = EntitySorter<Person>
.OrderByDescending("Address.City")
.ThenBy("Id");
You need to use the LINQ Dynamic Query Library in order to pass parameters at runtime,
This will allow linq statements like
string orderedBy = "Description";
var query = (from p in products
orderby(orderedBy)
select p);
If your columnName is in a variable col, then
string col="name";
list.OrderBy(x=>x[col])
As what Martin Liversage said, you can define a Func<>before you pass it to OrderBy method, but I found an interesting way to do that.
You can define a dictionary from string to Func<> like this :
Dictionary<string, Func<Item, object>> SortParameters = new Dictionary<string, Func<Item, object>>()
{
{"Rank", x => x.Rank}
};
And use it like this :
yourList.OrderBy(SortParameters["Rank"]);
In this case you can dynamically sort by string.
In one answer above:
The simplest & the best solution:
mylist.OrderBy(s => s.GetType().GetProperty("PropertyName").GetValue(s));
There is an syntax error, ,null must be added:
mylist.OrderBy(s => s.GetType().GetProperty("PropertyName").GetValue(s,null));
I have got a collection. The coll has strings:
Location="Theater=1, Name=regal, Area=Area1"
Location="Theater=34, Name=Karm, Area=Area4445"
and so on. I have to extract just the Name bit from the string. For example, here I have to extract the text 'regal' and group the query. Then display the result as
Name=regal Count 33
Name=Karm Count 22
I am struggling with the query:
Collection.Location.GroupBy(????);(what to add here)
Which is the most short and precise way to do it?
Yet another Linq + Regex approach:
string[] Location = {
"Theater=2, Name=regal, Area=Area1",
"Theater=2, Name=regal, Area=Area1",
"Theater=34, Name=Karm, Area=Area4445"
};
var test = Location.Select(
x => Regex.Match(x, "^.*Name=(.*),.*$")
.Groups[1].Value)
.GroupBy(x => x)
.Select(x=> new {Name = x.Key, Count = x.Count()});
Query result for tested strings
Once you've extracted the string, just group by it and count the results:
var query = from location in locations
let name = ExtractNameFromLocation(location)
group 1 by name in grouped
select new { Name=grouped.Key, Count=grouped.Count() };
That's not particularly efficient, however. It has to do all the grouping before it does any counting. Have a look at this VJ article for an extension method for LINQ to Objects,
and this one about Push LINQ which a somewhat different way of looking at LINQ.
EDIT: ExtractNameFromLocation would be the code taken from answers to your other question, e.g.
public static string ExtractNameFromLocation(string location)
{
var name = (from part in location.Split(',')
let pair = part.Split('=')
where pair[0].Trim() == "Name"
select pair[1].Trim()).FirstOrDefault();
return name;
}
Here is another LINQ alternative solution with a working example.
static void Main(string[] args)
{
System.Collections.Generic.List<string> l = new List<string>();
l.Add("Theater=1, Name=regal, Area=Area"); l.Add("Theater=34, Name=Karm, Area=Area4445");
foreach (IGrouping<string, string> g in l.GroupBy(r => extractName(r)))
{
Console.WriteLine( string.Format("Name= {0} Count {1}", g.Key, g.Count()) );
}
}
private static string extractName(string dirty)
{
System.Text.RegularExpressions.Match m =
System.Text.RegularExpressions.Regex.Match(
dirty, #"(?<=Name=)[a-zA-Z0-9_ ]+(?=,)");
return m.Success ? m.Value : "";
}