create a dictionary of list from an array of pocos?
-2
Want to create a dictionary<string, list<string>>
from a result set that has a list of:
class catalog{
public string Name { get; set; }
public string CategoryName { get; set; }
public bool CategoryDeleted { get; set; }
}
I want the key to be the CategoryName and the value to be a List of Names.
Each Categories can have the same Name associated with it. One categoryname to many reportnames and it looks like this.
{Name = "rp1", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp2", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp3", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp1", CategoryName=cat2, CategoryDeleted = 0 }
{Name = "rp2", CategoryName=cat2, CategoryDeleted = 0 }
I'd like a clean linq query that does this concisely.
what I have so far:
var dic = new Dictionary<string, List<string>>();
catalog.Select(x => x.CategoryName).Distinct().ToList().ForEach(x =>
{
dic.Add(x, catalog.Where(t => t.CategoryName == x).Select(t => t.ReportName).ToList());
});
I want to know if I can improve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
thanks!
c# linq dictionary
asked Nov 21 '18 at 22:13
melmackmelmack
406
add a comment |
-2
Want to create a dictionary<string, list<string>>
from a result set that has a list of:
class catalog{
public string Name { get; set; }
public string CategoryName { get; set; }
public bool CategoryDeleted { get; set; }
}
I want the key to be the CategoryName and the value to be a List of Names.
Each Categories can have the same Name associated with it. One categoryname to many reportnames and it looks like this.
{Name = "rp1", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp2", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp3", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp1", CategoryName=cat2, CategoryDeleted = 0 }
{Name = "rp2", CategoryName=cat2, CategoryDeleted = 0 }
I'd like a clean linq query that does this concisely.
what I have so far:
var dic = new Dictionary<string, List<string>>();
catalog.Select(x => x.CategoryName).Distinct().ToList().ForEach(x =>
{
dic.Add(x, catalog.Where(t => t.CategoryName == x).Select(t => t.ReportName).ToList());
});
I want to know if I can improve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
thanks!
c# linq dictionary
asked Nov 21 '18 at 22:13
melmackmelmack
406
I want to know if I can imporve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
– melmack
Nov 21 '18 at 22:18
Also note you're not iterating it twice, you're iterating it once plus once more for each category.
– Servy
Nov 21 '18 at 22:21
right. added now.
– melmack
Nov 21 '18 at 22:21
2
Use GroupBy followed by ToDictionary.
– Nikola Markovinović
Nov 21 '18 at 22:23
1
Don't you rather need a lookup?items.ToLookup(c => c.CategoryName, c => c.Name)
– Antonín Lejsek
Nov 22 '18 at 2:17
add a comment |
-2
-2
-2
Want to create a dictionary<string, list<string>>
from a result set that has a list of:
class catalog{
public string Name { get; set; }
public string CategoryName { get; set; }
public bool CategoryDeleted { get; set; }
}
I want the key to be the CategoryName and the value to be a List of Names.
Each Categories can have the same Name associated with it. One categoryname to many reportnames and it looks like this.
{Name = "rp1", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp2", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp3", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp1", CategoryName=cat2, CategoryDeleted = 0 }
{Name = "rp2", CategoryName=cat2, CategoryDeleted = 0 }
I'd like a clean linq query that does this concisely.
what I have so far:
var dic = new Dictionary<string, List<string>>();
catalog.Select(x => x.CategoryName).Distinct().ToList().ForEach(x =>
{
dic.Add(x, catalog.Where(t => t.CategoryName == x).Select(t => t.ReportName).ToList());
});
I want to know if I can improve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
thanks!
c# linq dictionary
asked Nov 21 '18 at 22:13
melmackmelmack
406
Want to create a dictionary<string, list<string>>
from a result set that has a list of:
class catalog{
public string Name { get; set; }
public string CategoryName { get; set; }
public bool CategoryDeleted { get; set; }
}
I want the key to be the CategoryName and the value to be a List of Names.
Each Categories can have the same Name associated with it. One categoryname to many reportnames and it looks like this.
{Name = "rp1", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp2", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp3", CategoryName=cat1, CategoryDeleted = 0 }
{Name = "rp1", CategoryName=cat2, CategoryDeleted = 0 }
{Name = "rp2", CategoryName=cat2, CategoryDeleted = 0 }
I'd like a clean linq query that does this concisely.
what I have so far:
var dic = new Dictionary<string, List<string>>();
catalog.Select(x => x.CategoryName).Distinct().ToList().ForEach(x =>
{
dic.Add(x, catalog.Where(t => t.CategoryName == x).Select(t => t.ReportName).ToList());
});
I want to know if I can improve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
thanks!
c# linq dictionary
c# linq dictionary
asked Nov 21 '18 at 22:13
melmackmelmack
406
asked Nov 21 '18 at 22:13
melmackmelmack
406
edited Nov 21 '18 at 22:20
melmack
asked Nov 21 '18 at 22:13
melmackmelmack
406
asked Nov 21 '18 at 22:13
melmackmelmack
406
asked Nov 21 '18 at 22:13
melmackmelmack
406
406
I want to know if I can imporve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
– melmack
Nov 21 '18 at 22:18
Also note you're not iterating it twice, you're iterating it once plus once more for each category.
– Servy
Nov 21 '18 at 22:21
right. added now.
– melmack
Nov 21 '18 at 22:21
2
Use GroupBy followed by ToDictionary.
– Nikola Markovinović
Nov 21 '18 at 22:23
1
Don't you rather need a lookup?items.ToLookup(c => c.CategoryName, c => c.Name)
– Antonín Lejsek
Nov 22 '18 at 2:17
add a comment |
I want to know if I can imporve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
– melmack
Nov 21 '18 at 22:18
Also note you're not iterating it twice, you're iterating it once plus once more for each category.
– Servy
Nov 21 '18 at 22:21
right. added now.
– melmack
Nov 21 '18 at 22:21
2
Use GroupBy followed by ToDictionary.
– Nikola Markovinović
Nov 21 '18 at 22:23
1
Don't you rather need a lookup?items.ToLookup(c => c.CategoryName, c => c.Name)
– Antonín Lejsek
Nov 22 '18 at 2:17
I want to know if I can imporve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
– melmack
Nov 21 '18 at 22:18
I want to know if I can imporve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
– melmack
Nov 21 '18 at 22:18
Also note you're not iterating it twice, you're iterating it once plus once more for each category.
– Servy
Nov 21 '18 at 22:21
Also note you're not iterating it twice, you're iterating it once plus once more for each category.
– Servy
Nov 21 '18 at 22:21
right. added now.
– melmack
Nov 21 '18 at 22:21
right. added now.
– melmack
Nov 21 '18 at 22:21
2
2
Use GroupBy followed by ToDictionary.
– Nikola Markovinović
Nov 21 '18 at 22:23
Use GroupBy followed by ToDictionary.
– Nikola Markovinović
Nov 21 '18 at 22:23
1
1
Don't you rather need a lookup?
items.ToLookup(c => c.CategoryName, c => c.Name)– Antonín Lejsek
Nov 22 '18 at 2:17
Don't you rather need a lookup?
items.ToLookup(c => c.CategoryName, c => c.Name)– Antonín Lejsek
Nov 22 '18 at 2:17
add a comment |
2 Answers
2
active
oldest
votes
2
Here is one more compact solution.
Dictionary<string, List<string>> dictionary = catalogs
.GroupBy(catalog => catalog.CategoryName, catalog => catalog.Name)
.ToDictionary(grouping => grouping.Key, grouping => grouping.ToList());
answered Nov 21 '18 at 22:27
AlesDAlesD
2,53829
add a comment |
2
You need to use grouping:
var dict = items.GroupBy(c => c.CategoryName).ToDictionary(g => g.Key, g => g.Select(c => c.Name));
answered Nov 21 '18 at 22:29
KrzysztofKrzysztof
244215
add a comment |
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2 Answers
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active
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2 Answers
2
active
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2
Here is one more compact solution.
Dictionary<string, List<string>> dictionary = catalogs
.GroupBy(catalog => catalog.CategoryName, catalog => catalog.Name)
.ToDictionary(grouping => grouping.Key, grouping => grouping.ToList());
answered Nov 21 '18 at 22:27
AlesDAlesD
2,53829
add a comment |
2
Here is one more compact solution.
Dictionary<string, List<string>> dictionary = catalogs
.GroupBy(catalog => catalog.CategoryName, catalog => catalog.Name)
.ToDictionary(grouping => grouping.Key, grouping => grouping.ToList());
answered Nov 21 '18 at 22:27
AlesDAlesD
2,53829
add a comment |
2
2
2
Here is one more compact solution.
Dictionary<string, List<string>> dictionary = catalogs
.GroupBy(catalog => catalog.CategoryName, catalog => catalog.Name)
.ToDictionary(grouping => grouping.Key, grouping => grouping.ToList());
answered Nov 21 '18 at 22:27
AlesDAlesD
2,53829
Here is one more compact solution.
Dictionary<string, List<string>> dictionary = catalogs
.GroupBy(catalog => catalog.CategoryName, catalog => catalog.Name)
.ToDictionary(grouping => grouping.Key, grouping => grouping.ToList());
answered Nov 21 '18 at 22:27
AlesDAlesD
2,53829
answered Nov 21 '18 at 22:27
AlesDAlesD
2,53829
answered Nov 21 '18 at 22:27
AlesDAlesD
2,53829
answered Nov 21 '18 at 22:27
AlesDAlesD
2,53829
2,53829
add a comment |
add a comment |
2
You need to use grouping:
var dict = items.GroupBy(c => c.CategoryName).ToDictionary(g => g.Key, g => g.Select(c => c.Name));
answered Nov 21 '18 at 22:29
KrzysztofKrzysztof
244215
add a comment |
2
You need to use grouping:
var dict = items.GroupBy(c => c.CategoryName).ToDictionary(g => g.Key, g => g.Select(c => c.Name));
answered Nov 21 '18 at 22:29
KrzysztofKrzysztof
244215
add a comment |
2
2
2
You need to use grouping:
var dict = items.GroupBy(c => c.CategoryName).ToDictionary(g => g.Key, g => g.Select(c => c.Name));
answered Nov 21 '18 at 22:29
KrzysztofKrzysztof
244215
You need to use grouping:
var dict = items.GroupBy(c => c.CategoryName).ToDictionary(g => g.Key, g => g.Select(c => c.Name));
answered Nov 21 '18 at 22:29
KrzysztofKrzysztof
244215
answered Nov 21 '18 at 22:29
KrzysztofKrzysztof
244215
answered Nov 21 '18 at 22:29
KrzysztofKrzysztof
244215
answered Nov 21 '18 at 22:29
KrzysztofKrzysztof
244215
244215
add a comment |
add a comment |
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I want to know if I can imporve my query to not have to reference the catalog list twice. once to iterate and select my keys, then another to initialize the value when I make a dictionary add.
– melmack
Nov 21 '18 at 22:18
Also note you're not iterating it twice, you're iterating it once plus once more for each category.
– Servy
Nov 21 '18 at 22:21
right. added now.
– melmack
Nov 21 '18 at 22:21
2
Use GroupBy followed by ToDictionary.
– Nikola Markovinović
Nov 21 '18 at 22:23
1
Don't you rather need a lookup?
items.ToLookup(c => c.CategoryName, c => c.Name)– Antonín Lejsek
Nov 22 '18 at 2:17