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Questions tagged [trygetvalue]

"TryGetValue" usually refers to an operation of value lookup at dictionary (or map) by a specified key. "Try" here means that it is a failsafe method, i.e. in case of the key is not contained by the dictionary, some indicator of missing value is returned.

When tagging a question with , be sure to tag it with the language being used, and with the related data structure, like , , , , , , or .

In C++

std::map<Key, T, Compare, Allocator>::find: returns an iterator, which is empty in case of no such key.

In .NET

Dictionary<TKey, TValue>.TryGetValue: returns true or false depending on whether the provided key was found and a value as an out parameter.

In Python

dict.get: Returns the value, which is substituted by a provided default in case of no such a key.

In Java

Map<K, V>.get: Returns the value or null if this map contains no mapping for the key.

For questions about Mapping Functions over collections of data, Please Use tag.

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C# Extension static class fails when reading Properties with TryGetValue

I have the below Extension (not mine, borrowed for my implementation, but altered a bit) and I am wondering why is the TryGetValue below failing, despite the fact the the pair (string, object - well, var in my case) seem correct. public static class…
Nick
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popup Div td get value using Jquery

Below is the div which i am trying to show in a popup. How do i get the td value from the popup. When trying to call the popupClick(). it returns undefined. I have attached the code below. Thanks in advance for the help. function btnSmartResult()…
karthisena
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c# - ConcurrentDictionary.TryGet(): Do I need to use while?

I am not sure I fully understand TryGet method. When does it exactly return false - when the internal lock is locked and it means I should use while if I want to get value (knowing it's there)? Or this while is somehow embedded in this function…
bgee
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In a Dictionary TryGetValue, how do I write the out parameter (and get it's values) if it's part of a class?

Past question thread and link to fullpast code HERE I create my dictionary with a class for a parameter so it can hold two string values. Now I'm trying to write a TryGetValue to out both of the strings in this class: public class…
Aroueterra
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using TryGetValue from key and adding not working as intened

I have this code to retrieve a value(integer array) out of a dictionary Then increment one of the elements inside the integer array based on the if statement it is in.. Dictionary ResultDic = new Dictionary(); …
Marno vN
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Why is this this method with an 'out' parameter saying it isn't set?

UGH! Well I was going to post this as a question because I didn't know why I was seeing the error... but of course it's now so obvious when I see it. Slapping myself in the head now. I'll leave it here for fun though. See if you can catch…
Mark A. Donohoe
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specify type of delegate parameter

im trying to use TryGetValue. to Invoke a delegate inside Method i use dictionary to select one delegate and then Invoke it. the dictionary type is Dictionary> _meshActions; and the action type is Action So here it…
M.kazem Akhgary
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How to Avoid Updating item searched by Dictionary?

In .NET WinForms C# app, I have a Dictionary collection named listItems. I store data in it on start of the app. In a static class I have as follows: // listItems is populated bt reading a file. // No other…
Tvd
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get JSON attribute value

I have converted an XML document to JSON using Newtonsoft Library in .NET. Some of the converted XML nodes have attributes, like this (once converted): "HandID": { "@Room": "", "#text": "1" }, In JavaScript the Hand is an object. Question: how…
user3553401
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Navigation Context Try Get Value

Why my string email only contains the value of aux on the OnNavigatedTo method? Why when I try to use my string email on the Main method the value becomes null? public string email; protected override void…
Gustavo Mendonça
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how to getValue of editText on same activity in android?

I am not been able to print value enter by the user in editText on the same activity in android
shweta
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How do I output my Dictionary>?

I'm really stuck here now with my Dictionary Output: I have this Code to "fill" the dictionary (basically there are 2 of them): Dictionary> newDictionary = new Dictionary
Luca
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How to take a value from a private method

I have created using NetBeans a jSlider ChangeEvent, with the following code: public class Slider extends javax.swing.JFrame { public Slider() { initComponents; field.getText(); String fieldVal = field.getText(); …
Iulia
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Windows Phone 8 Error with NavigationContext.QueryString.TryGetValue()

I've run into an issue with passing parameters between pages. OnNavigatedTo is definitely being called but the if statement keeps returning false, when it should return true. Can anyone out there shoot me in the right direction? The following is…
Connal Sumlin
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CodeIgniter get value from Max

How to get value from MAX('table')? This is the code Array ( [0] => stdClass Object ( [applicant_id] => A001 [MAX(education_type)] => 6 ) ) To get the value from 'applicant_id' i simply using…
user3654785
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