lookup

lock(dictionaryX) { dictionaryX.TryGetValue(key, out value); } is locking necessary while doing lookups to a Dictionary ? THe program is multithreaded, and while adding key/value to dict. dict is being locked. Locking is only needed when you are synchronizing access to a resource between threads. As long as there are not mulitple threads involved then locking is not needed here. In the context of updating and reading the value from multiple threads, yes a lock is absolutely necessary. In fact if you're using 4.0 you should consider switching to one of the collections specifically designed for

I have a variable of type Dictionary<MyType, List<MyOtherType>> I want to convert it to a Lookup<MyType, MyOtehrType> . I wanted to use Lambda functions to first, flatten the dictionary and then convert this to Lookup using the ToLookup() . I got stuck with the dictionary. I thought about using SelectMany but can't get it working. Anyone has got an idea how to do it? How about: var lookup = dictionary.SelectMany(pair => pair.Value, (pair, Value) => new { pair.Key, Value }) .ToLookup(pair => pair.Key, pair => pair.Value); It does feel like a little bit of a waste doing this when the dictionary

I have a Perl script that is counting the number of occurrences of various strings in a text file. I want to be able to check if a certain string is not yet a key in the hash. Is there a better way of doing this altogether? Here is what I am doing: foreach $line (@lines){ if(($line =~ m|my regex|) ) { $string = $1; if ($string is not a key in %strings) # "strings" is an associative array { $strings{$string} = 1; } else { $n = ($strings{$string}); $strings{$string} = $n +1; } } } I believe to check if a key exists in a hash you just do if (exists $strings{$string}) { ... } else { ... } I would

I am trying to achieve a basic lookup using INDEX and MATCH. My layout is: Sheet 1 NAME | SITE | DATE Sheet 2 NAME | SITE | DATE I want the 'SITE' column in Sheet 1 to automatically populate with the SITE from Sheet 2 where NAME and DATE match. What I've Tried =INDEX('Sheet2'!B:B,MATCH(A1,'Sheet2'!A:A,0)) This will successfully match NAME, but how can I incorporate an additional MATCH into the formula to match on both NAME and DATE? I suggest the conventional solution to problems of this kind is to concatenate the pair of search terms (ie a helper column) and to add the concatenated pairs to

I seems that in spite of the fact that there are online plenty of algorithms and functions for generating unique combinations of any size from a list of unique items, there is none available in case of a list of non-unique items (i.e. list containing repetitions of same value.) The question is how to generate ON-THE-FLY in a generator function all the unique combinations from a non-unique list without the computational expensive need of filtering out duplicates? Now as there is a bounty motivated answer to the question it is easier to provide more clarity about what I expect to achieve: First

I'm interested in getting access to a full WHOIS database in order to expand on a domain-profile project I'm working on. I know ARIN provides this database only to non-commercial researchers and every WHOIS provider I know of (including ARIN itself) has rate-limiting. I also know, however, some commercial services that already exist (like the registrant lookup section of domaintools.com, which can search for domains by registrant name) which are impossible unless the site has direct access to a cached copy of the WHOIS database. Any idea how they got ahold of their data? There is no publicly

I want add a domain registration in a website written with PHP. So I need a whois lookup service. What do I need to do? What's are its steps? Do I need a database, API or ... ? Help me please I cannot speak to the quality of any of the following services, but here are a few offerings: WhoAPI Hexillion Whois API DomainTools API WhoisXMLAPI 来源： https://stackoverflow.com/questions/8648794/what-is-the-best-way-to-create-a-whois-lookup

How can I rewrite the following pseudocode in C++? real array sine_table[-1000..1000] for x from -1000 to 1000 sine_table[x] := sine(pi * x / 1000) I need to create a sine_table lookup table. You can reduce the size of your table to 25% of the original by only storing values for the first quadrant, i.e. for x in [0,pi/2]. To do that your lookup routine just needs to map all values of x to the first quadrant using simple trig identities: sin(x) = - sin(-x), to map from quadrant IV to I sin(x) = sin(pi - x), to map from quadrant II to I To map from quadrant III to I, apply both identities, i.e.