hashtable

Print a hash table function (it does not work and the program it crashes)

由 荒凉一梦 提交于 2020-04-18 00:49:46
问题 I just started to learn about hash tables.I have to write a program which displays and list a hash table.The keys are a list of words from a txt file which is a dictionary. I wrote the code but I got a breakpoint in main file when I call the list function to print the table.The program crashes.How to fix it ?The list function is in functions file. Here is code I wrote: main file #include <iostream> #include <fstream> #include <string> #include "header.h" using namespace std; int main() { elem

Can I add a key named 'keys' to a hashtable without overriding the 'keys' member

由 血红的双手。 提交于 2020-04-13 07:11:10
问题 It seems that I cannot add an arbitrary key name to a hashtable without overriding a member with that name if it already exists. I create a hash table ( $x ) and add two keys, one and two : $x = @{} $x['one'] = 1 $x['two'] = 2 The added keys are then shown by evaluating $x.Keys : $x.Keys This prints: one two If I add another key, named keys , it overrides the already existing member: $x['Keys'] = 42 $x.Keys This now prints: 42 I am not sure if I find this behavior desirable. I had expected $x

Can I add a key named 'keys' to a hashtable without overriding the 'keys' member

由 十年热恋 提交于 2020-04-13 07:10:17
问题 It seems that I cannot add an arbitrary key name to a hashtable without overriding a member with that name if it already exists. I create a hash table ( $x ) and add two keys, one and two : $x = @{} $x['one'] = 1 $x['two'] = 2 The added keys are then shown by evaluating $x.Keys : $x.Keys This prints: one two If I add another key, named keys , it overrides the already existing member: $x['Keys'] = 42 $x.Keys This now prints: 42 I am not sure if I find this behavior desirable. I had expected $x

Java集合：Map接口总结

由 故事扮演 提交于 2020-03-08 11:12:06
一、HashMap 基于哈希表的 Map 接口的实现，允许存入 null 值和 null 键，无序存储且线程不同步； HashMap 初始容量默认为16，扩容一定是2的指数，加载因子默认值为0.75； HashMap采用Iterator方式迭代，可直接迭代键值对； 迭代 collection 视图所需的时间与 HashMap 实例的“容量”（桶的数量）及其大小（键-值映射关系数）成比例。所以，如果迭代性能很重要，则不要将初始容量设置得太高（或将加载因子设置得太低）。 建议多看源码，如果觉得晦涩可以戳 这里 看源码解析。 安利网址：http://www.admin10000.com/document/3322.html，个人觉得分析的挺好 JDK1.8+HashMap的改进 JDK1.8以前是采用的数组+链表形式存储，JDK1.8+是采用的是数组+链表/红黑树 JDK1.8+，当bucket节点数小于等于6时，转换为链表形式；当节点数大于等于8时，转换为红黑树形式 JDK1.8以前，HashMap的put()方法、get()源码如下： put(): public V put(K key, V value) { // HashMap允许存放null键和null值。 // 当key为null时，调用putForNullKey方法，将value放置在数组第一个位置。 if (key ==

HashMap Hashtable 的区别

由 时间秒杀一切 提交于 2020-03-01 04:55:24
Hashtable 和 HashMap 作为 Map 的基本特性 两者都实现了Map接口，基本特性相同 - 对同一个Key，只会有一个对应的value值存在 - 如何算是同一个Key？ 首先，两个key对象的hash值相同，其次，key对象的equals方法返回真 内部数据结构 Hashtable和HashMap的内部数据结构相似 其基本内部数据结构是一个Entry数组 ( transient Entry[] table) - 数组元素为实现Map.Entry<K,V>接口的类，Hashtable和HashMap各自实现了自己的Entry类。 - Entry包含一个Key-value对，以及一个next指针指向另一个Entry。多个Entry可以组成一个单向链表。 常用操作 数据插入操作： put(key,value) - 根据Key的hash值计算出该Entry所应存放的位置（数组下标） - 若该数组元素为空，直接放置Entry到此处 - 若多个不同的Key所计算得到的数组下标相同，新加入的Key-value对（Entry）会被加入到Entry单向链表中。Hashtable和HashMap都是将其插入链表首部. - 若已经有相同的Key存在于这个链表中，则，新的value值会取代老的value - 当Map中存放的Entry数量超过其限制（ 数组长度 * 负荷因子）时

How do you pass a hash table to a function in PowerShell?

由 只愿长相守 提交于 2020-01-24 02:02:33
问题 When passing a hash table to my PowerShell function, it complains that it receives an object. Function ExtendHash(){ param( [hashtable] $source, [hashtable] $extender ) ... } And the caller: $hash1 = @{One = 1; Two = 2} $hash2 = @{Two = 22; three = 3} ExtendHash($hash1, $hash2) Cannot convert the System.Object[] value of type System.Object[] to type System.Collection.Hashtable So how do I make this work? Suggestions? Also, am I missing something built-in? I want the same pattern as what

C dictionary/map

由 蹲街弑〆低调 提交于 2020-01-23 03:57:12
问题 I want to map struct members so I can eliminate if branches in a loop. What is the best way or convention to implement this in C? I suppose it could be a 2 dimensional array instead...then I could map integers to the char keys? char chunk[32]; int n; int i; char *ptr = config; while (*ptr != '\0') { int items_read = sscanf(ptr, "%31[^;]%n", chunk, &n); if(chunk[0] == 'S' && chunk[1] == 'P') { for(i=0;i<GLOBAL_MEAS_CUTOFF; i++) { theMeas[i].signal_path = atoi(&chunk[2]); } } if(chunk[0] == 'T'

Getting NullPointerException from Hashtable while using GObject method

由 ♀尐吖头ヾ 提交于 2020-01-21 15:21:07
问题 So I try to create a small Zombie-Shooter game. I use a GTurtle class from ACM package (jtf.acm.org). I have additional thread for a GTurtle, which is a GObject. I have a run method with while loop, that is checking if boolean is true, if it is - this.forward() method gets executed. I tried running game and pressing button, if it is W or D, boolean in GTurtle object gets changed and Thread executes action. Then I get this exception: java.lang.NullPointerException at java.util.Hashtable.put

how to convert a hash table in string in java

由 天大地大妈咪最大 提交于 2020-01-16 10:03:29
问题 I'm new in java and i want to convert a hash table in the form of a string, with each pair separated by any special character. I'm little confuse how to apply loop on the hash table and extract values from. Please explain me how to do this. Thanks in advance public String parseHashtable(Hashtable detailHashtable){ String hashstring= ""; foreach(){ hashstring += key + "=" + hashtable[key] + "|"; } return hashstring; } 回答1: String seperator = "|"; StringBuilder sb = new StringBuilder(); Set

hsearch_r overwrites hash table

由 让人想犯罪 __ 提交于 2020-01-16 01:10:27
问题 I'm trying to see if I can put a new feature into inotifywait that during the watching phase tracks the list of directories that did not receive any event on them, and before it quits, it prints the list. As of now, inotifywait is capable of showing on directories that received an event. What I'm looking for is for a list of directories that did not receive any event. To achieve this, I'm taking the following approach. While inotifywait is placing watches, generate an array of all the
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