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I am trying to create a dictionary that can hold multiple values per key, and I have created an class called Pair that consists of two strings. I have defined idDictionary to contain a string as the key, and Pair as the value, but I am unsure how to write the ToDictionary statement as this concept is new to me, and I couldn't find any examples of this.
Dictionary<string, Pair<string, string>> idDictionary = new Dictionary<string, Pair<string, string>>();
I know with a regular generic Dictionary of I would simply use something like this:
idDictionary = resultData.Rows.Select(row => row.Split(','))
.ToDictionary(id => id[0], id => id[1]);
I am not sure how I would implement something similar for the object called Pair. Maybe I'm missing something really simple, but many thanks to those with answers.
EDIT to include full code block and more thorough explanation
The original code block is here (with a generic dictionary). The reason I am changing this is due to the fact that if there is more than 1 value per key, the application errors out due to duplicate keys.
private List<ImportItem<T>> ProcessReportResult(CSVTable resultData, ICollection<ImportItem<T>> data, Func<T, string> keyFilter)
{
WriteLog("{1}{0} records found.{1}", resultData.Rows.Length, Environment.NewLine);
//key = Order Number; value = Order ID
var idDictionary = resultData.Rows.Select((row => row.Split(','))).ToDictionary(id => id[0], id => id[1]);
idDictionary.ForEach(id => WriteLog("Input Id = {0} - Matching record Id = {1}", id.Key, id.Value));
var processList = data.Where(item => idDictionary.ContainsKey(keyFilter(item.DataItem))).ToList();
processList.ForEach(item => item.id = idDictionary[keyFilter(item.DataItem)]);
return processList;
}
A genral solution to get the one to many key value store can be achieved via grouping but that would require to have value as List of items. If I try to explain it via your given sample then the query to convert the rows to per key multi value store can be created by:
idDictionary =
resultData.Rows
.GroupBy(row => row.Id, row => row.Split(','))
.ToDictionary(g => g.Key, g => g.ToList());
Update:
Specific solution to your problem. Assuming that data would have structure something like:
List<Row> rows = new List<Row>{
new Row{
values = "1,A"
},
new Row{
values = "2,C,D,E"
},
new DataRow{
values = "3,E,X,CV,B"
},
};
You can use the Group here as well to get the Key, Value(List). Note, Here I have skipped the first value which is already captured as key at index 0.
var idDictionary =
rows.GroupBy(row => row.values.Split(',')[0],
row => row.values.Split(',').Skip(1))
.ToDictionary(g => g.Key, g => g.ToList());
This will give you the result like:
/* output -
|1, (A)|
|2, (C,D,E)|
|3, (E,X,CV,B)|
*/
Though you have to change the implementation for fetching the values via List.
But this solution will prevent the Program if there are more than one values found per key.
Not sure exactly what you need maybe this simple example will help?
idDictionary = resultData.Rows
.Select((row => row.Split(',')))
.ToDictionary<string, Pair<string, string>>
(id => id[0],id => new Pair(id[1],id[1]));
This version of ToDictionary takes two functions, one that returns the key and one that returns the value for each item in the enumeration.
You'll have to decide whether you want a tuple-based approach (or pair even) if you know how many items are in each row or if you need to consider that each row may have a different number of items.
// Setup sample data
var resultData = new
{
Rows = new string[] { "1,A,B,C", "2,A,B", "3,A,B,C,D" }
};
// If same length for each row, tuple would work easily
// Dictionary<string, Tuple<string, string>>
var tuples = resultData.Rows
.Select(r => r.Split(','))
.ToDictionary(
r => r[0],
r => Tuple.Create(r[1], r[2])
);
// If length is variable, then some type of collection could be better
// Dictionary<string, List<string>>
var lists = resultData.Rows
.Select(r => r.Split(','))
.ToDictionary(
r => r[0],
r => r.Skip(1).ToList() // Skip adding id element
);
Here is the output for the 1st item to compare each:
?lists["1"]
Count = 3
[0]: "A"
[1]: "B"
[2]: "C"
?tuples["1"]
{(A, B)}
Item1: "A"
Item2: "B"
The original code block is here (with a generic dictionary). The reason I am changing this is due to the fact that if there is more than 1 value per key, the application errors out due to duplicate keys.
Seems like what you are looking for is ToLookup
"Lookup<TKey, TElement>
represents a collection of keys each mapped to one or more values."
.
var idDictionary = resultData.Rows.Select((row => row.Split(',')))
.ToLookup(id => id[0], id => id[1]);
EDIT
A short sample:
var lines = new string[] { "a,b", "a,c", "d,e" };
var dict = lines.Select(line => line.Split(','))
.ToLookup(x => x[0], x => x[1]);
result:
Key: a Value: [b,c]
Key: e Value: [e]
Sample usage:
Console.WriteLine(string.Join(",", dict["a"]));
I have a collection of strings like the following:
List<string> codes = new List<string>
{
"44.01", "44.02", "44.03", "44.04", "44.05", "44.06", "44.07", "44.08", "46", "47.10"
};
Each string is made up of two components separated by a full stop - a prefix code and a subcode. Some of the strings don't have sub codes.
I want to be able combine the strings whose prefixes are the same and output them as follows with the other codes also:
44(01,02,03,04,05,06,07,08),46,47.10
I'm stuck at the first hurdle of this, which is how to identify and group together the codes whose prefix values are the same, so that I can combine them into a single string as you can see above.
You can do:
var query = codes.Select(c =>
new
{
SplitArray = c.Split('.'), //to avoid multiple split
Value = c
})
.Select(c => new
{
Prefix = c.SplitArray.First(), //you can avoid multiple split if you split first and use it later
PostFix = c.SplitArray.Last(),
Value = c.Value,
})
.GroupBy(r => r.Prefix)
.Select(grp => new
{
Key = grp.Key,
Items = grp.Count() > 1 ? String.Join(",", grp.Select(t => t.PostFix)) : "",
Value = grp.First().Value,
});
This is how it works:
Split each item in the list on the delimiter and populate an anonymous type with Prefix, Postfix and original value
Later group on Prefix
after that select the values and the post fix values using string.Join
For output:
foreach (var item in query)
{
if(String.IsNullOrWhiteSpace(item.Items))
Console.WriteLine(item.Value);
else
Console.WriteLine("{0}({1})", item.Key, item.Items);
}
Output would be:
44(01,02,03,04,05,06,07,08)
46
47.10
Try this:-
var result = codes.Select(x => new { SplitArr = x.Split('.'), OriginalValue = x })
.GroupBy(x => x.SplitArr[0])
.Select(x => new
{
Prefix= x.Key,
subCode = x.Count() > 1 ?
String.Join(",", x.Select(z => z.SplitArray[1])) : "",
OriginalValue = x.First().OriginalValue
});
You can print your desired output like this:-
foreach (var item in result)
{
Console.Write("{0}({1}),",item.Prefix,item.subCode);
}
Working Fiddle.
Outlined idea:
Use Dictionary<string, List<string>> for collecting your result
in a loop over your list, use string.split() .. the first element will be your Dictionary key ... create a new List<string> there if the key doesn't exist yet
if the result of split has a second element, append that to the List
use a second loop to format that Dictionary to your output string
Of course, linq is possible too, e.g.
List<string> codes = new List<string>() {
"44.01", "44.05", "47", "42.02", "44.03" };
var result = string.Join(",",
codes.OrderBy(x => x)
.Select(x => x.Split('.'))
.GroupBy(x => x[0])
.Select((x) =>
{
if (x.Count() == 0) return x.Key;
else if (x.Count() == 1) return string.Join(".", x.First());
else return x.Key + "(" + string.Join(",", x.Select(e => e[1]).ToArray()) + ")";
}).ToArray());
Gotta love linq ... haha ... I think this is a monster.
You can do it all in one clever LINQ:
var grouped = codes.Select(x => x.Split('.'))
.Select(x => new
{
Prefix = int.Parse(x[0]),
Subcode = x.Length > 1 ? int.Parse(x[1]) : (int?)null
})
.GroupBy(k => k.Prefix)
.Select(g => new
{
Prefix = g.Key,
Subcodes = g.Where(s => s.Subcode.HasValue).Select(s => s.Subcode)
})
.Select(x =>
x.Prefix +
(x.Subcodes.Count() == 1 ? string.Format(".{0}", x.Subcodes.First()) :
x.Subcodes.Count() > 1 ? string.Format("({0})", string.Join(",", x.Subcodes))
: string.Empty)
).ToArray();
First it splits by Code and Subcode
Group by you Code, and get all Subcodes as a collection
Select it in the appropriate format
Looking at the problem, I think you should stop just before the last Select and let the data presentation be done in another part/method of your application.
The old fashioned way:
List<string> codes = new List<string>() {"44.01", "44.05", "47", "42.02", "44.03" };
string output=""
for (int i=0;i<list.count;i++)
{
string [] items= (codes[i]+"..").split('.') ;
int pos1=output.IndexOf(","+items[0]+"(") ;
if (pos1<0) output+=","+items[0]+"("+items[1]+")" ; // first occurence of code : add it
else
{ // Code already inserted : find the insert point
int pos2=output.Substring(pos1).IndexOf(')') ;
output=output.Substring(0,pos2)+","+items[1]+output.Substring(pos2) ;
}
}
if (output.Length>0) output=output.Substring(1).replace("()","") ;
This will work, including the correct formats for no subcodes, a single subcode, multiple subcodes. It also doesn't assume the prefix or subcodes are numeric, so it leaves leading zeros as is. Your question didn't show what to do in the case you have a prefix without subcode AND the same prefix with subcode, so it may not work in that edge case (44,44.01). I have it so that it ignores the prefix without subcode in that edge case.
List<string> codes = new List<string>
{
"44.01", "44.02", "44.03", "44.04", "44.05", "44.06", "44.07", "44.08", "46", "47.10"
};
var result=codes.Select(x => (x+".").Split('.'))
.Select(x => new
{
Prefix = x[0],
Subcode = x[1]
})
.GroupBy(k => k.Prefix)
.Select(g => new
{
Prefix = g.Key,
Subcodes = g.Where(s => s.Subcode!="").Select(s => s.Subcode)
})
.Select(x =>
x.Prefix +
(x.Subcodes.Count() == 0 ? string.Empty :
string.Format(x.Subcodes.Count()>1?"({0})":".{0}",
string.Join(",", x.Subcodes)))
).ToArray();
General idea, but i'm sure replacing the Substring calls with Regex would be a lot better as well
List<string> newCodes = new List<string>()
foreach (string sub1 in codes.Select(item => item.Substring(0,2)).Distinct)
{
StringBuilder code = new StringBuilder();
code.Append("sub1(");
foreach (string sub2 in codes.Where(item => item.Substring(0,2) == sub1).Select(item => item.Substring(2))
code.Append(sub2 + ",");
code.Append(")");
newCodes.Add(code.ToString());
}
You could go a couple ways... I could see you making a Dictionary<string,List<string>> so that you could have "44" map to a list of {".01", ".02", ".03", etc.} This would require you processing the codes before adding them to this list (i.e. separating out the two parts of the code and handling the case where there is only one part).
Or you could put them into a a SortedSet and provide your own Comparator which knows that these are codes and how to sort them (at least that'd be more reliable than grouping them alphabetically). Iterating over this SortedSet would still require special logic, though, so perhaps the Dictionary to List option above is still preferable.
In either case you would still need to handle a special case "46" where there is no second element in the code. In the dictionary example, would you insert a String.Empty into the list? Not sure what you'd output if you got a list {"46", "46.1"} -- would you display as "46(null,1)" or... "46(0,1)"... or "46(,1)" or "46(1)"?
My problem is that I am trying to take a body of text from a text box for example
"Spent the day with "insert famous name" '#excited #happy #happy"
then I want to count how many times each hashtag appears in the body, which can be any length of text.
so the above would return this
excited = 1
happy = 2
I Was planning on using a dictionary but I am not sure how I would implement the search for the hashtags and add to the dictionary.
This is all I have so far
string body = txtBody.Text;
Dictionary<string, string> dic = new Dictionary<string, string>();
foreach(char c in body)
{
}
thanks for any help
This can be achieved with a couple of LINQ methods:
var text = "Spent the day with <insert famous name> #excited #happy #happy";
var hashtags = text.Split(new[] { ' ' })
.Where(word => word.StartsWith("#"))
.GroupBy(hashtag => hashtag)
.ToDictionary(group => group.Key, group => group.Count());
Console.WriteLine(string.Join("; ", hashtags.Select(kvp => kvp.Key + ": " + kvp.Value)));
This will print
#excited: 1; #happy: 2
This will find any hashtags in a string of the form a hash followed by one or more non-whitespace characters and create a dictionary of them versus their count.
You did mean Dictionary<string, int> really, didn't you?
var input = "Spent the day with \"insert famous name\" '#excited #happy #happy";
Dictionary<string, int> dic =
Regex
.Matches(input, #"(?<=\#)\S+")
.Cast<Match>()
.Select(m => m.Value)
.GroupBy(s => s)
.ToDictionary(g => g.Key, g => g.Count());
I would like to use the .net Regex.Split method to split this input string into an array. It must group the word.
Input: **AAA**-1111,**AAA**-666,**SMT**-QWQE,**SMT**-TTTR
Expected output:
**AAA** : 1111,666
**SMT** : QWQE,TTTR
What pattern do I need to use?
As the comment on the question notes, you cannot do this in a single step (regex or not).
So:
Split on commas.
Split on dash (but keep the pairs)
Group by the first part of each pair.
Something like:
var result = select outer in input.Split(",")
let p = outer.Split('-') // will be string[2]
select new { identifier = p[0], value = p[1] }
into pair
group by pair.identifier into g
select new {
identifier = g.Key
values = String.Join(",", g)
}
This should give you an IEnumerable with a key-string and a string listing (separated by comma) the values fore each:
var input = "AAA-1111,AAA-666,SMT-QWQE,SMT-TTTR";
var list = input.Split(',')
.Select(pair => pair.Split('-'))
.GroupBy(pair => pair.First())
.Select(grp =>
new{
key = grp.Key,
items = String.Join(",", grp.Select(x => x[1]))
});
You can then use it for example like this (if you just want to output the values):
string output = "";
foreach(var grp in list)
{
output += grp.key + ": " + grp.items + Environment.NewLine;
}
FWIW here's the same solution in fluent syntax which might be easier to understand:
string input = "AAA-1111,AAA-666,SMT-QWQE,SMT-TTTR";
Dictionary<string, string> output = input.Split(',') // first split by ','
.Select(el => el.Split('-')) // then split each inner element by '-'
.GroupBy(el => el.ElementAt(0), el => el.ElementAt(1)) // group by the part that comes before '-'
.ToDictionary(grp => grp.Key, grp => string.Join(",", grp)); // convert to a dictionary with comma separated values
-
output["AAA"] // 1111,666
output["SMT"] // QWQE,TTTR
I have a text file stored as a string variable. The text file is processed so that it only contains lowercase words and spaces. Now, say I have a static dictionary, which is just a list of specific words, and I want to count, from within the text file, the frequency of each word in the dictionary. For example:
Text file:
i love love vb development although i m a total newbie
Dictionary:
love, development, fire, stone
The output I'd like to see is something like the following, listing both the dictionary word and its count. If it makes coding simpler, it can also only list the dictionary word that appeared in the text.
===========
WORD, COUNT
love, 2
development, 1
fire, 0
stone, 0
============
Using a regex (eg "\w+") I can get all the word matches, but I have no clue how to get the counts that are also in the dictionary, so I'm stuck. Efficiency is crucial here since the dictionary is quite large (~100,000 words) and the text files are not small either (~200kb each).
I appreciate any kind help.
You can count the words in the string by grouping them and turning it into a dictionary:
Dictionary<string, int> count =
theString.Split(' ')
.GroupBy(s => s)
.ToDictionary(g => g.Key, g => g.Count());
Now you can just check if the words exist in the dictionary, and show the count if it does.
var dict = new Dictionary<string, int>();
foreach (var word in file)
if (dict.ContainsKey(word))
dict[word]++;
else
dict[word] = 1;
Using Groovy regex facilty, i would do it as below :-
def input="""
i love love vb development although i m a total newbie
"""
def dictionary=["love", "development", "fire", "stone"]
dictionary.each{
def pattern= ~/${it}/
match = input =~ pattern
println "${it}" + "-"+ match.count
}
Try this. The words variable is obviously your string of text. The keywords array is a list of keywords you want to count.
This won't return a 0 for dictionary words that aren't in the text, but you specified that this behavior is okay. This should give you relatively good performance while meeting the requirements of your application.
string words = "i love love vb development although i m a total newbie";
string[] keywords = new[] { "love", "development", "fire", "stone" };
Regex regex = new Regex("\\w+");
var frequencyList = regex.Matches(words)
.Cast<Match>()
.Select(c => c.Value.ToLowerInvariant())
.Where(c => keywords.Contains(c))
.GroupBy(c => c)
.Select(g => new { Word = g.Key, Count = g.Count() })
.OrderByDescending(g => g.Count)
.ThenBy(g => g.Word);
//Convert to a dictionary
Dictionary<string, int> dict = frequencyList.ToDictionary(d => d.Word, d => d.Count);
//Or iterate through them as is
foreach (var item in frequencyList)
Response.Write(String.Format("{0}, {1}", item.Word, item.Count));
If you want to achieve the same thing without using RegEx since you indicated you know everything is lower case and separated by spaces, you could modify the above code like so:
string words = "i love love vb development although i m a total newbie";
string[] keywords = new[] { "love", "development", "fire", "stone" };
var frequencyList = words.Split(' ')
.Select(c => c)
.Where(c => keywords.Contains(c))
.GroupBy(c => c)
.Select(g => new { Word = g.Key, Count = g.Count() })
.OrderByDescending(g => g.Count)
.ThenBy(g => g.Word);
Dictionary<string, int> dict = frequencyList.ToDictionary(d => d.Word, d => d.Count);