key-value

I have searched for key value stores that support integer keys and integer values. LevelDB seems a good option, though I can't find any information on whether integer values/keys are supported You can store pretty much anything in LevelDB. You provide opaque slices of data into LevelDB via the Slice structure. Here is an example: int intKey = 256; int intValue = 256*256; Slice key((char*)&intKey, sizeof(int)); Slice value((char*)&intValue, sizeof(int)); db->Put(leveldb::WriteOptions(), key, value); And that's pretty much it! However , one thing to note is that while it's generally fine to

I bumbed into one of those moments when I just lose the focus and start wondering on a silly question: var a = { b: "value" } What is the typeof 'b' and I don't mean the typeof "value", but the actual Key labeled as b? background: I started wondering about this when I had to create a key which is a string: var a = { "b": "value" } because at a later point it is referenced as: a["b"] And then eneded up wondering the original question. In object literal terms, b is a property. Properties are either strings or symbols in JavaScript, although when defining the property name inside an object

Confused about the following declaration: constructor(controls: {[key: string]: AbstractControl}, optionals?: {[key: string]: boolean}, validator?: ValidatorFn, asyncValidator?: AsyncValidatorFn) What is the type of the controls (first parameter)? Is it an object which is an array of key value pairs where key is string and value is AbstractControl? Thanks! Yes, like you guessed, it's a js object with key as string and AbstractControl as values. For example: { "control1": new Control(), "control2": new Control() } Edit You can declare a variable to be of this type in two ways: let controls: {

In .Net 2.5 I can usually get an equality comparison (==) between a value and its type default if (myString == default(string)) However I get the following exception when I try to run an equality comparison on a default KeyValuePair and a KeyValuePair Code Sample (from a pre-extension method, proto-lambda static ListUtilities class :) ) public static TKey FirstKeyOrDefault<TKey, TValue>(Dictionary<TKey, TValue> lookups, Predicate<KeyValuePair<TKey, TValue>> predicate) { KeyValuePair<TKey, TValue> pair = FirstOrDefault(lookups, predicate); return pair == default(KeyValuePair<TKey, TValue>) ?

I am trying to match key-value pairs that appear at the end of (long) strings. The strings look like (I replaced the "\n") my_str = "lots of blah key1: val1-words key2: val2-words key3: val3-words" so I expect matches "key1: val1-words", "key2: val2-words" and "key3: val3-words". The set of possible key names is known. Not all possible keys appear in every string. At least two keys appear in every string (if that makes it easier to match). val-words can be several words. key-value pairs should only be matched at the end of string. I am using Python re module. I was thinking re.compile('(?:tag1

I have a hash like {:key1 => "value1", :key2 => "value2"} And I have a variable k which will have the value as 'key1' or 'key2' . I want to get the value of k into a variable v . Is there any way to achieve this with out using if or case ? A single line solution is preferred. Please help. Convert the key from a string to a symbol, and do a lookup in the hash. hash = {:key1 => "value1", :key2 => "value2"} k = 'key1' hash[k.to_sym] # or iow, hash[:key1], which will return "value1" Rails uses this class called HashWithIndifferentAccess that proves to be very useful in such cases. I know that you

Normally, we write the mapper in the form : public static class Map extends Mapper<**LongWritable**, Text, Text, IntWritable> Here the input key-value pair for the mapper is <LongWritable, Text> - as far as I know when the mapper gets the input data its goes through line by line - so the Key for the mapper signifies the line number - please correct me if I am wrong. My question is : If I give the input key-value pair for mapper as <Text, Text> then it is giving the error java.lang.ClassCastException: org.apache.hadoop.io.LongWritable cannot be cast to org.apache.hadoop.io.Text Is it a

一 数据库概述 1. 数据库？？？ 　　什么是数据库呢？ 　　先来看看百度怎么说的 数据库，简而言之可视为电子化的文件柜——存储电子文件的处所，用户可以对文件中的数据运行新增、截取、更新、删除等操作。 所谓“数据库”系以一定方式储存在一起、能予多个用户共享、具有尽可能小的冗余度、与应用程序彼此独立的数据集合。 　　百度的貌似不好理解啊，让我说啊，数据库是存储数据的地方，超哥，你这不是废话么？这位同学，你你你你你说的对，哈哈，存数据的地方是存在哪里呢，存在硬盘上，为什么不是存在内存里面，因为内存无法永久保存。之前我们存数据都是使用的文件，在一个word文档里面写一些羞羞的网址，然后保存，就存储到硬盘上了。有同学就会说了，超哥，我这通过文件不是也将数据保存上了吗？是的，没毛病，但是你想，通过文件来操作数据，效率是不是很低，首先打开关闭就比较慢，其次是我们操作起来也比较麻烦，对不对，如果我想记录一条关于我个人信息的数据，我使用文档来存，是不是很不友好，并且我们要查数据的时候，看图1：图1是一个word里面记录的信息，如果我想查询出所有人的名字，这个操作是不是就很难搞定了，来来来，配合起来~~，你应该说是的，那我就接着说，有同学可能就会说了，老师我用excel啊，看图2，一列就搞定了，没毛病，但是你想打开操作excel效率低不低。并且通过你自己写的程序来操作这些文件是不是很麻烦

I found a lot of related questions with answers talking about for...in loops and using hasOwnProperty but nothing I do works properly. All I want to do is check whether or not a key exists in an array and if not, add it. I start with an empty array then add keys as the page is scrubbed with jQuery. Initially, I hoped that something simple like the following would work: (using generic names) if (!array[key]) array[key] = value; No go. Followed it up with: for (var in array) { if (!array.hasOwnProperty(var)) array[key] = value; } Also tried: if (array.hasOwnProperty(key) == false) array[key] =