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What is the lifetime of a static variable in a C++ function?

If a variable is declared as static in a function's scope it is only initialized once and retains its value between function ... plonk = "When will I die?"; } Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql server - Is there a combination of "LIKE" and "IN" in SQL?

In SQL I (sadly) often have to use "LIKE" conditions due to databases that violate nearly every rule of normalization ... this is possible in any RDBMS at all. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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java - Why is volatile used in double checked locking

From Head First design patterns book, the singleton pattern with double checked locking has been implemented as ... double checked locking i.e performance? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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php - How to retrieve images from MySQL database and display in an html tag

I created a MySQL database with a table using phpmyadmin. I created this table with a BLOB column to hold a jpeg file. ... so I can display it in the <img> tag? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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TypeError: 'list' object is not callable in python

I am novice to Python and following a tutorial. There is an example of list in the tutorial : example = list( ... wrong. I searched SO this but it is different. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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xml - Using Xpath With Default Namespace in C#

I've got an XML document with a default namespace. I'm using a XPathNavigator to select a set of nodes using ... How can I include the namespace in my select? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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Can you split/explode a field in a MySQL query?

I have to create a report on some student completions. The students each belong to one client. Here are the tables ( ... c.`courseNames`)[e.`courseId`] FROM ... Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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javascript - How to move an element into another element?

I would like to move one DIV element inside another. For example, I want to move this (including all children): <div id=" ... div id="source"> ... </div> </div> Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How does free know how much to free?

In C programming, you can pass any kind of pointer you like as an argument to free, how does it know the ... around the extra variable of the array's length? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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java - Are getters and setters poor design? Contradictory advice seen

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asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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Can't connect to local MySQL server through socket '/var/mysql/mysql.sock' (38)

I am having a big problem trying to connect to mysql. When I run: /usr/local/mysql/bin/mysql start I have the ... --sockets I get --socket [/tmp/mysql.sock] Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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jquery - XMLHttpRequest Origin null is not allowed Access-Control-Allow-Origin for file:/// to file:/// (Serverless)

I'm trying to create a website that can be downloaded and run locally by launching its index file. All the files are ... js/. How can I do to fix this issue? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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Android saving file to external storage

I have a little issue with creating a directory and saving a file to it on my android application. I'm using ... only if he connect his device as Disk Drive? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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datatable - OleDB & mixed Excel datatypes : missing data

I have an Excel worksheet I want to read into a datatable - all is well except for one particular column in my ... in values like n######. How can I do this? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c# - Memory Leak using StreamReader and XmlSerializer

I've been googling for the past few hours and trying different things but can't seem to the bottom of this.... ... (); but that doesn't seem to do anything. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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powershell - Unexpected ConvertTo-Json results? Answer: it has a default -Depth of 2

Why do I get unexpected ConvertTo-Json results, why do I get values like System.Collections.Hashtable and/or ... repeating questions due to the same cause. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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bash - How do I prompt for Yes/No/Cancel input in a Linux shell script?

I want to pause input in a shell script, and prompt the user for choices. The standard Yes, No, or Cancel ... do I accomplish this in a typical bash prompt? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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algorithm - How can building a heap be O(n) time complexity?

Can someone help explain how can building a heap be O(n) complexity? Inserting an item into a heap is O(log n), ... (which is log n levels). What am I missing? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c# - How to escape braces (curly brackets) in a format string in .NET

How can brackets be escaped in using string.Format? For example: String val = "1,2,3" String.Format(" foo {{0}} ... {0}. Is there a way to escape the brackets? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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pointers - Deleting Objects in JavaScript

I'm a bit confused with JavaScript's delete operator. Take the following piece of code: var obj = { helloText: " ... way, my testing was done in Safari 4.) Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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402 views

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sql - Postgresql GROUP_CONCAT equivalent?

I have a table and I'd like to pull one row per id with field values concatenated. In my table, for ... for PostgreSQL, or another way to accomplish this? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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javascript - Convert json data to a html table

Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c# - Find and extract a number from a string

I have a requirement to find and extract a number contained within a string. For example, from these strings: string test = ... = "test 99" How can I do this? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rest - 400 BAD request HTTP error code meaning?

I have a JSON request which I'm posting to a HTTP URL. Should this be treated as 400 where requestedResource field exists ... 't exist at all? [{blah:"Roman"}] Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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database design - Calculating and saving space in PostgreSQL

I have a table in pg like so: CREATE TABLE t ( a BIGSERIAL NOT NULL, -- 8 b b SMALLINT, -- 2 b c ... option? Would there be a speed penalty? Any other ideas? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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ios - How to return value from Alamofire

I am making url calls thru an API that I created using swift as follows: class API { let apiEndPoint = " ... () println(api.returnData) // returnData is empty Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c# - better way to load 2 dropdown in mvc

This is how i am loading on page load state and city dropdown: My Controller method: This is the first method which is calling ... + "']").remove(); } function insertSuccess() { a...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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144 views

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Android Endless List

How can I create a list where when you reach the end of the list I am notified so I can load more items? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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