We Keep Coding

Error report of C # groupby using AsQueryable

var commodity = _appDbContext.ArchivesCCommodity.Where(lambda)
.GroupJoin(_appDbContext.ArchivesCCommoditySpecification, a => a.Code, b => b.Commodity, (a, b) => new { a, b })
.SelectMany(a => a.b.DefaultIfEmpty(), (a, b) => new { a.a, b })
.GroupJoin(_appDbContext.ArchivesCSpecificationDetail, a => a.a.a.b.SpecificationDetail, d => d.Code, (a, d) => new { a, d })
.SelectMany(a => a.d.DefaultIfEmpty(), (a, d) => new
{
Commodity = a.a.a.Code,
CommodityName = a.a.a.Name,
SpecificationDetailName = d.Name,
OrderSN = d.OrderSN
}).AsQueryable().OrderBy(a => a.OrderSN).GroupBy(a => new { a.Commodity, a.CommodityName })
.Select(a => new
{
Commodity = a.Key.Commodity,
CommodityName = a.Key.CommodityName,
SpecificationDetailName = string.Join(" - ", a.Select(a => a.SpecificationDetailName)),
SpecificationDetailTotal = string.Join(" - ", a.Select(a => a.SpecificationDetailName)) == "" ? 0 : a.Count()
});
Where .AsQueryable() will cause an error
.AsQueryable()
.OrderBy(a => a.OrderSN)
.GroupBy(a => new { a.Commodity, a.CommodityName })
No error will be reported when changing to AsEnumerable()
.ASEnumerable()
.OrderBy(a => a.OrderSN)
.GroupBy(a => new { a.Commodity, a.CommodityName })
But I don't want to send this code to the database for the time being, because it will be sent after paging query. I don't know how to deal with it?
//////////////I pasted my complete code and talked about my actual needs
Query the code and query the database page by page. For example, only one page and 10 rows of records are checked. Here is OK.
var AA= _appDbContext.ArchivesCCommodity.Where(lambda)
.GroupJoin(_appDbContext.ArchivesCCommoditySpecification, a => a.Code, b => b.Commodity, (a, b) => new { a, b })
.SelectMany(a => a.b.DefaultIfEmpty(), (a, b) => new { a.a, b })
.GroupJoin(_appDbContext.ArchivesCSpecificationDetail, a => a.a.b.SpecificationDetail, d => d.Code, (a, d) => new { a, d })
.SelectMany(a => a.d.DefaultIfEmpty(), (a, d) => new
{
Commodity = a.a.a.a.a.Code,
CommodityName = a.a.a.a.a.Name,
SpecificationDetailName = d.Name,
OrderSN = d.OrderSN
});
PageHealper<object> page = new PageHealper<object>();
page.Start(pageNum, pageSize);
page = await page.RestPage(AA);
At this time, I grouped and sorted again, and now I found that:
It is not to operate the paging query results, but to query all the AA databases.
Based on the previous pagination query, the number of rows and page numbers are obtained. Here, the number of rows is changed by grouping and merging.
That's why I want to put grouping and sorting together, and finally pagination.
var BB = AA.AsEnumerable().OrderBy(a => a.OrderSN).GroupBy(a => new { a.Commodity, a.CommodityName, a.Specification, a.SpecificationName })
.Select(a => new
{
Commodity = a.Key.Commodity,
CommodityName = a.Key.CommodityName,
SpecificationDetailName = string.Join(" - ", a.Select(a => a.SpecificationDetailName)),
SpecificationDetailTotal = string.Join(" - ", a.Select(a => a.SpecificationDetailName)) == "" ? 0 : a.Count()
}); ;
page.Data = BB.ToList<object>();
return page;

Checkout this article https://weblogs.asp.net/zeeshanhirani/using-asqueryable-with-linq-to-objects-and-linq-to-sql about what AsQueryable does.
I think you dont really need AsQueryable there... LINQ to SQL does not like something about that query.
It does not like the String.Join(...) because it cannot translate it.
So one thing you can do is put .AsEnumerable() after the GroupBy() this will do everything up to in SQL and everything after in memory.
Ex:
var commodity = _appDbContext.ArchivesCCommodity.Where(lambda)
.GroupJoin(_appDbContext.ArchivesCCommoditySpecification, a => a.Code, b => b.Commodity, (a, b) => new { a, b })
.SelectMany(a => a.b.DefaultIfEmpty(), (a, b) => new { a.a, b })
.GroupJoin(_appDbContext.ArchivesCSpecificationDetail, a => a.a.a.b.SpecificationDetail, d => d.Code, (a, d) => new { a, d })
.SelectMany(a => a.d.DefaultIfEmpty(), (a, d) => new
{
Commodity = a.a.a.Code,
CommodityName = a.a.a.Name,
SpecificationDetailName = d.Name,
OrderSN = d.OrderSN
}).OrderBy(a => a.OrderSN).GroupBy(a => new { a.Commodity, a.CommodityName })
.AnEnumerable()
.Select(a => new
{
Commodity = a.Key.Commodity,
CommodityName = a.Key.CommodityName,
SpecificationDetailName = string.Join(" - ", a.Select(a => a.SpecificationDetailName)),
SpecificationDetailTotal = string.Join(" - ", a.Select(a => a.SpecificationDetailName)) == "" ? 0 : a.Count()
});

Mysql to Linq query

MySQL Query
select MAX(os.aggregate_date) as lastMonthDay,os.totalYTD
from (SELECT aggregate_date,Sum(YTD) AS totalYTD
FROM tbl_aggregated_tables
WHERE subscription_type = 'Subcription Income'
GROUP BY aggregate_date) as os
GROUP by MONTH(os.aggregate_date),YEAR(os.aggregate_date)
ORDER BY lastMonthDay;
converted to this LINQ query
var income = context.tbl_aggregated_tables
.Where(s => s.subscription_type == "Subcription Income")
.GroupBy(s => s.aggregate_date)
.Select(result => new
{
date = result.Key,
ytdsum = result.Select(x => x.YTD).Sum()
})
.GroupBy(s => new { month = s.date.Month, year = s.date.Year })
.Select(
// select max data and take its ytdsum value
).ToList();
The purpose of second grouping is to find the max day of each month with a year.
Now, How to select the max date of each month and its ytdsum after the second Grouping?
update
income = context.tbl_aggregated_tables
.Where(s => s.subscription_type == "Subcription Income")
.GroupBy(s => s.aggregate_date)
.Select(result => new
{
date = result.Key,
ytdsum = result.Select(x => x.YTD).Sum()
})
.GroupBy(s => new { s.date.Month, s.date.Year })
.Select(
x => x.Max(s => s.date)
).ToList()
this way it's only return the dates and i could not return the full object of the list including ytdSum.

This should work:
var income = context.tbl_aggregated_tables
.Where(s => s.subscription_type == "Subcription Income")
.GroupBy(s => s.aggregate_date)
.Select(result => new
{
date = result.Key,
ytdsum = result.Select(x => x.YTD).Sum()
})
.GroupBy(s => new { month = s.date.Month, year = s.date.Year })
.Select(
x => x.OrderByDescending(k => k.date).First()
).ToList();
income now is a list of objects, each of them have date and ytdsum

this worked good but it takes much more time than the original mysql query.
var income = context.tbl_aggregated_tables
.Where(s => s.subscription_type == "Subcription Income"
)
.GroupBy(s => s.aggregate_date)
.Select(result => new
{
date = result.Key,
ytdsum = result.Select(x => x.YTD).Sum()
})
.GroupBy(s => new { s.date.Month, s.date.Year })
.Select(
x => x.OrderByDescending(s => s.date)
)
.ToList()
.Select(el => el.FirstOrDefault())
.OrderBy(s=>s.date);

Append index number to duplicated string value in a list - by using Lambda

I have a IList<string>() which holds some string values, and there could be duplicated items in the list. What I want is to append a index number to end of the string to eliminate the duplication.
For example, I have these values in my list: StringA, StringB, StringC, StringA, StringA, StringB. And I want the result looks like: StringA1, StringB1, StringC, StringA2, StringA3, StringB2. I need to retain the original order in list.
Is there a way I can just use one Lambda expression?

You are looking for something like this:
yourList.GroupBy(x => x)
.SelectMany(g => g.Select((x,idx) => g.Count() == 1 ? x : x + idx))
.ToList();
Edit: If the element order matters, here is another solution:
var counts = yourList.GroupBy(x => x).ToDictionary(x => x.Key, x => x.Count());
var values = counts.ToDictionary(x => x.Key, x => 0);
var list = yourList.Select(x => counts[x] > 1 ? x + ++values[x] : x).ToList();

You can do:
List<string> list = new List<string> { "StringA", "StringB", "StringC", "StringA", "StringA", "StringB" };
var newList =
list.Select((r, i) => new { Value = r, Index = i })
.GroupBy(r => r.Value)
.Select(grp => grp.Count() > 1 ?
grp.Select((subItem, i) => new
{
Value = subItem.Value + (i + 1),
OriginalIndex = subItem.Index
})
: grp.Select(subItem => new
{
Value = subItem.Value,
OriginalIndex = subItem.Index
}))
.SelectMany(r => r)
.OrderBy(r => r.OriginalIndex)
.Select(r => r.Value)
.ToList();
and you will get:
StringA1,StringB1,StringC,StringA2,StringA3,StringB2
If you don't want to preserve order then you can do:
var newList = list.GroupBy(r => r)
.Select(grp => grp.Count() > 1 ?
grp.Select((subItem, i) => subItem + (i + 1))
: grp.Select(subItem => subItem))
.SelectMany(r => r)
.ToList();

This uses some lambda expressions and linq to do it, maintaining the order but I'd suggested a function with a foreach loop and yield return would be better.
var result = list.Aggregate(
new List<KeyValuePair<string, int>>(),
(cache, s) =>
{
var last = cache.Reverse().FirstOrDefault(p => p.Key == s);
if (last == null)
{
cache.Add(new KeyValuePair<string, int>(s, 0));
}
else
{
if (last.Value = 0)
{
last.Value = 1;
}
cache.Add(new KeyValuePair<string, int>(s, last.Value + 1));
}
return cache;
},
cache => cache.Select(p => p.Value == 0 ?
p.Key :
p.Key + p.Value.ToString()));

How to use predicate method in many to many relation entity framework linq lambda expression?

My problem is hard to solve. i need your help this problem. There is many to many relation in codefirst. But i can not resolve this. i would like to use Predicate func. But i can not resolve it? how to use "Method(Predicate func)"
public int Method<T>(Predicate<T> func)
{
var s1 = this.Uow.X.GetAll().Where(func)
.SelectMany(a => a.OrganizationalUnits.Where(q => Identity.Y.Contains(q.Z)))
.GroupBy(t => t, (k, g) => new
{
Tag = k,
Count = g.Count()
})
.OrderByDescending(g => g.Count);
var s2 = this.Uow.X.GetAll().Where(func)
.SelectMany(a => a.Classes.Where(q => Identity.Y.Contains(q.K)))
.GroupBy(t => t, (k, g) => new
{
Tag = k,
Count = g.Count()
})
.OrderByDescending(g => g.Count);
var s3 = this.Uow.X.GetAll().Where(func)
.SelectMany(a => a.Courses.Where(q => Identity.Y.Contains(q.L)))
.GroupBy(t => t, (k, g) => new
{
Tag = k,
Count = g.Count()
})
.OrderByDescending(g => g.Count);
return s1.ToString().Count() + s2.ToString().Count() + s3.ToString().Count();
}

Here is the way to do it. I also removed the ToString()s on the last line since you don't need an object to be a string to count it.
Call like this: int result = Method<TypeGoesHere>(p => p == aValue);
public int Method<T>(Expression<Func<T, Boolean>> Predicate)
{
var s1 = this.Uow.X.GetAll().Where(Predicate)
.SelectMany(a => a.OrganizationalUnits.Where(q => Identity.Y.Contains(q.Z)))
.GroupBy(t => t, (k, g) => new
{
Tag = k,
Count = g.Count()
})
.OrderByDescending(g => g.Count);
var s2 = this.Uow.X.GetAll().Where(Predicate)
.SelectMany(a => a.Classes.Where(q => Identity.Y.Contains(q.K)))
.GroupBy(t => t, (k, g) => new
{
Tag = k,
Count = g.Count()
})
.OrderByDescending(g => g.Count);
var s3 = this.Uow.X.GetAll().Where(Predicate)
.SelectMany(a => a.Courses.Where(q => Identity.Y.Contains(q.L)))
.GroupBy(t => t, (k, g) => new
{
Tag = k,
Count = g.Count()
})
.OrderByDescending(g => g.Count);
return s1.Count() + s2.Count() + s3.Count();
}
I think you probably want an extension method for whatever type this is. It would look like this (if thisType was type of this). This does not need to be a template since you (but not me) know the type of X.GetAll(). I'm guessing List<int> which would make T int. I've also changed the code to be briefer but have the same functionality. (It might be your original code was doing the wrong thing but this does the same thing.)
Call like this:
thisType something = new something();
someType aValue = X; // don't know the type here.
// do stuff with something
int result = something.Method(p => p == aValue);
Code:
public static int Method(this thisType me, Expression<Func<someType, Boolean>> Predicate)
{
var allOfEm = me.Uow.X.GetAll().Where(Predicate);
var s1 = allOfEm
.SelectMany(a => a.OrganizationalUnits.Where(q => Identity.Y.Contains(q.Z)))
.Distinct();
var s2 = allOfEm
.SelectMany(a => a.Classes.Where(q => Identity.Y.Contains(q.K)))
.Distinct();
var s3 = allOfEm
.SelectMany(a => a.Courses.Where(q => Identity.Y.Contains(q.L)))
.Distinct();
return s1.Count() + s2.Count() + s3.Count();
}

How to compare 2 list by characters content and its correspondents double values?

I have 2 lists: a string list and a double list with same length and with same index of correspondence. I need to compare all the strings, find the indexes of the list that has the same characters, independent of its order, and delete the highest double value that corresponds to both,
Example:
List<string> str= new List<string>();
str.add("efc");
str.add("abc");
str.add("cde");
str.add("cab");
str.add("fbc");
List<double> vlr= new List<double>();
vlr.add(0.1);
vlr.add(0.5);
vlr.add(0.4);
vlr.add(0.2);
vlr.add(0.3);
and this case, "abc" => (0.5) must be deleted because "cab" has the same characters AND lower correspondent value =>(0.2).
There is a lambda expression for this 2 arrays??
What I've tried:
var distinct = list .Select((str, idx) => new { Str = str, Idx = idx })
.GroupBy(pair => new HashSet<char>(pair.Str), HashSet<char>.CreateSetComparer())
.Select(grp => grp.OrderBy(p => p.Idx).First())
.ToList();

Here's one way to solve it:
// Pair the strings with their correspondence values
var pairs = str.Zip(vlr, (s, d) => new {s, d});
// Group using a sorted string, eliminating differences due to character order
var groups = pairs.GroupBy(x => new string(x.s.ToCharArray().OrderBy(c => c).ToArray()));
// For each group, retain the item with the lowest correspondence value
var filtered = groups.Select(x => x.OrderBy(y => y.d).First().s);

var newDict = str.Zip(vlr, (s, d) => new { s, d })
.GroupBy(x => String.Join("", x.s.OrderBy(y => y)))
.Select(g => g.OrderBy(x => x.d).First())
.ToDictionary(x => x.s, x => x.d);

here is the code:
var group = str.GroupBy(s => string.Join("", s.ToCharArray().OrderBy(c => c)));
var _vlr = group.Select(g => g.Min(s => vlr[str.IndexOf(s)]));
var _str = group.Select(g => g.OrderBy(s => vlr[str.IndexOf(s)]).First());
and the result: