hashtable

问题 I'm using the Tokyo Cabinet database through the PyTyrant module, storing the data in a hash table (*.tch file). When the file reaches 65 GB in size, the following bug occurs: when a new entry is added to the database, querying the new key gives a "no such key error". However, the new key is listed when I query for a list of all keys. Furthermore, the problematic entries cannot be deleted from the table. Can anyone explain this? EDIT: output of 'tcrmgr inform -st -port 1978 localhost'

问题 I would like to have a little clarification on the definiton of a bucket in SAS hashtable. The question is exactly about the hashexp parameter. According to the SAS DOCs, hashexp is: The hash object's internal table size, where the size of the hash table is 2n. The value of HASHEXP is used as a power-of-two exponent to create the hash table size. For example, a value of 4 for HASHEXP equates to a hash table size of 24, or 16. The maximum value for HASHEXP is 20. The hash table size is not

问题 I would like to have a little clarification on the definiton of a bucket in SAS hashtable. The question is exactly about the hashexp parameter. According to the SAS DOCs, hashexp is: The hash object's internal table size, where the size of the hash table is 2n. The value of HASHEXP is used as a power-of-two exponent to create the hash table size. For example, a value of 4 for HASHEXP equates to a hash table size of 24, or 16. The maximum value for HASHEXP is 20. The hash table size is not

问题 Lets say you have a set: foo = {1, 2, 3, 4, 5} In the book I am currently reading, Pro Python, it says that using foo.pop() will pop an arbitrary number from that selection. BUT...When I try it out, it pops 1, then 2, then 3... Does it do it arbitrarily, or is this just a coincidence? 回答1: The reason it says it is arbitrary is because there is no guarantee about the ordering it will pop out. Since you just created the set, it may be storing the elements in a "nice" order, and thus .pop()

问题 Lets say you have a set: foo = {1, 2, 3, 4, 5} In the book I am currently reading, Pro Python, it says that using foo.pop() will pop an arbitrary number from that selection. BUT...When I try it out, it pops 1, then 2, then 3... Does it do it arbitrarily, or is this just a coincidence? 回答1: The reason it says it is arbitrary is because there is no guarantee about the ordering it will pop out. Since you just created the set, it may be storing the elements in a "nice" order, and thus .pop()

问题 I need debug some old code that uses a Hashtable to store response from various threads. I need a way to go through the entire Hashtable and print out both keys and the data in the Hastable. How can this be done? 回答1: foreach(string key in hashTable.Keys) { Console.WriteLine(String.Format("{0}: {1}", key, hashTable[key])); } 回答2: I like: foreach(DictionaryEntry entry in hashtable) { Console.WriteLine(entry.Key + ":" + entry.Value); } 回答3: public static void PrintKeysAndValues( Hashtable

问题 I need debug some old code that uses a Hashtable to store response from various threads. I need a way to go through the entire Hashtable and print out both keys and the data in the Hastable. How can this be done? 回答1: foreach(string key in hashTable.Keys) { Console.WriteLine(String.Format("{0}: {1}", key, hashTable[key])); } 回答2: I like: foreach(DictionaryEntry entry in hashtable) { Console.WriteLine(entry.Key + ":" + entry.Value); } 回答3: public static void PrintKeysAndValues( Hashtable

问题 I'm looking to implement an IEqualityComparer class that stores and compares floating point keys that are rounded to the nearest 0.01. In particular, I want to make sure I implement the GetHashCode method correctly. I would like to make this as efficient as possible. Can I use just use the float value itself as it's own hash? I could multiply by 100, cast to int and use an int as a key, but I'm curious if this can be done with float keys. Note: I would wrap the dictionary in a class to ensure

问题 I'm looking to implement an IEqualityComparer class that stores and compares floating point keys that are rounded to the nearest 0.01. In particular, I want to make sure I implement the GetHashCode method correctly. I would like to make this as efficient as possible. Can I use just use the float value itself as it's own hash? I could multiply by 100, cast to int and use an int as a key, but I'm curious if this can be done with float keys. Note: I would wrap the dictionary in a class to ensure

问题 I already know that we use HashMap when we have Key-Value pair and we use HashSet when we do not need repetitive data. But I always get confused where Hashtable comes into play. Is it a totally different data structure? Or both HashMap and HashSet use hash function to store data in Hashtable ? Thorough explanation will be really helpful . 回答1: More specific, HashSet uses internally a HashMap , look at the implementation of HashSet.java private transient HashMap<E,Object> map; As stated in a