OStack Q&A-Knowledge Sharing Community

0 votes

343 views

1 answer

multithreading - "implements Runnable" vs "extends Thread" in Java

From what time I've spent with threads in Java, I've found these two ways to write threads: With ... significant difference in these two blocks of code? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

149 views

1 answer

javascript - Can scripts be inserted with innerHTML?

I tried to load some scripts into a page using innerHTML on a <div>. It appears that the script loads into the DOM, but ... id="loader"></div> </body> </html> Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

376 views

1 answer

java - What is the reason behind "non-static method cannot be referenced from a static context"?

This question already has answers here: Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

762 views

1 answer

jsf - How to find out client ID of component for ajax update/render? Cannot find component with expression "foo" referenced from "bar"

The following code is inspired from PrimeFaces DataGrid + DataTable Tutorials and put into a <p:tab> of a <p:tabView> ... is this caused and how can I solve it? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

166 views

1 answer

python - Get the row(s) which have the max value in groups using groupby

How do I find all rows in a pandas data frame which have the max value for count column, after grouping by ['Sp','Mt'] ... MM2 S4 bg 10 MM4 S2 cb 8 MM4 S2 uyi 8 Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

99 views

1 answer

sql - ROW_NUMBER() in MySQL

Is there a nice way in MySQL to replicate the SQL Server function ROW_NUMBER()? For example: SELECT col1, col2, ... highest col3 for each (col1, col2) pair. Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

122 views

1 answer

javascript - How to remove all duplicates from an array of objects?

I have an object that contains an array of objects. things = new Object(); things.thing = new Array(); things. ... :"stuff"}, {place:"there",name:"morestuff"} Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

192 views

1 answer

c++ - When and why will a compiler initialise memory to 0xCD, 0xDD, etc. on malloc/free/new/delete?

I know that the compiler will sometimes initialize memory with certain patterns such as 0xCD and 0xDD. What I want ... in the debugger. How portable is this? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

194 views

1 answer

How do I add files in Git to the path of a former submodule?

I have a project that used to contain a submodule, at path mysubmodule. I installed the latest Git from source (1. ... 'mysubmodule' error. How do I fix this? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

309 views

1 answer

c# - Serialize and Deserialize Json and Json Array in Unity

I have a list of items send from a PHP file to unity using WWW. The WWW.text looks like: [ { "playerId": "1", " ... = {1}", kvp.Key, kvp.Value)); } Thanks! Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

109 views

1 answer

javascript - How can I tell if a DOM element is visible in the current viewport?

Is there an efficient way to tell if a DOM element (in an HTML document) is currently visible (appears in the viewport)? (The question refers to Firefox.) Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

65 views

1 answer

Performance optimization strategies of last resort

Closed. This question needs to be more focused. It is not currently accepting answers. Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

93 views

1 answer

javascript - Scroll to an element with jQuery

I have this input element: <input type="text" class="textfield" value="" id="subject" name="subject"> ... to use the default jQuery features to achieve this. Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

267 views

1 answer

version control - How do I undo the most recent local commits in Git?

I accidentally committed the wrong files to Git, but didn't push the commit to the server yet. How can I undo ... git commit was run. Is there a better way? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

299 views

1 answer

c# - The model item passed into the dictionary is of type .. but this dictionary requires a model item of type

This question and community wiki answer has been added to assist in closing out numerous unanswered questions as discussed in ... mean, and how do I fix it? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

184 views

1 answer

Using i and j as variables in MATLAB

i and j are very popular variable names (see e.g., this question and this one). For example, in loops: ... shouldn't they be used as variable names in MATLAB? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

77 views

1 answer

Syntax error on print with Python 3

This question already has answers here: Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

204 views

1 answer

r - Numbering rows within groups in a data frame

Working with a data frame similar to this: set.seed(100) df <- data.frame(cat = c(rep("aaa", 5), rep("bbb" ... 0.88216552 5 What would be a good way to do this? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

51 views

1 answer

How to get the difference between two arrays in JavaScript?

Is there a way to return the difference between two arrays in JavaScript? For example: var a1 = ['a', 'b']; var a2 = ['a', 'b', 'c', 'd']; // need ["c", "d"] Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

179 views

1 answer

.net - Deserialize JSON into C# dynamic object?

Is there a way to deserialize JSON content into a C# dynamic type? It would be nice to skip ... of classes in order to use the DataContractJsonSerializer. Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

146 views

1 answer

python - Iterating over dictionaries using 'for' loops

I am a bit puzzled by the following code: d = {'x': 1, 'y': 2, 'z': 3} for key in d: print (key ... Is key a special word in Python? Or is it simply a variable? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

528 views

1 answer

algorithm - Calculate distance between two latitude-longitude points? (Haversine formula)

How do I calculate the distance between two points specified by latitude and longitude? For clarification, ... relative accuracies of the approaches available. Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

197 views

1 answer

javascript - What is DOM Event delegation?

Can anyone please explain event delegation in JavaScript and how is it useful? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

123 views

1 answer

html - What to do Regular expression pattern doesn't match anywhere in string?

I am trying to match <input> type hidden fields using this pattern: /<input type="hidden" name= ... based RegEx Desktop Tool for testing regular expressions. Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

177 views

1 answer

Creating multiline strings in JavaScript

I have the following code in Ruby. I want to convert this code into JavaScript. What is the equivalent code in JS ... = <<"HERE" This Is A Multiline String HERE Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

76 views

1 answer

c++ - What is a lambda expression in C++11?

What is a lambda expression in C++11? When would I use one? What class of problem do they solve that wasn't ... A few examples, and use cases would be useful. Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

350 views

1 answer

What is the "N+1 selects problem" in ORM (Object-Relational Mapping)?

The "N+1 selects problem" is generally stated as a problem in Object-Relational mapping (ORM) discussions, ... have a more detailed explanation of the problem? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

146 views

1 answer

Why do I need to override the equals and hashCode methods in Java?

Recently I read through this Developer Works Document. The document is all about defining hashCode() and ... decision to implement these methods efficiently? Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

Categories

Recent questions

Just Browsing Browsing

Most popular tags