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Best way to test if a row exists in a MySQL table
I'm trying to find out if a row exists in a table. Using MySQL, is it better to do a query like this:
12 Answers
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How to use hex color values
I am trying to use hex color values in Swift, instead of the few standard ones that UIColor allows you to use, but I have no idea how to do it.
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Understanding exactly when a data.table is a reference to (vs a copy of) another data.table
I'm having a little trouble understanding the pass-by-reference properties of data.table . Some operations seem to 'break' the reference, and I'd like to understand exactly what's happening.
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LINGO使用指南 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...将被包含在主窗口之下。在主窗口内的标题为LINGO Model – LINGO1的窗口是LINGO的默认模型窗口，建立的模型都都要在该窗口内编码实现。下面举两个例子。
例1.1 如何在LINGO中求解如下的LP问题：
在模型窗口中输入如下代码：...
Difference between variable declaration syntaxes in Javascript (including global variables)?
Is there any difference between declaring a variable:
5 Answers
5
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Replacing NAs with latest non-NA value
In a data.frame (or data.table), I would like to "fill forward" NAs with the closest previous non-NA value. A simple example, using vectors (instead of a data.frame ) is the following:
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Stack vs heap allocation of structs in Go, and how they relate to garbage collection
I'm new to Go and I'm experiencing a bit of congitive dissonance between C-style stack-based programming where automatic variables live on the stack and allocated memory lives on the heap and and Python-style stack-based-programming where the only thing that lives on the stack are references/pointer...
Does Java support default parameter values?
I came across some Java code that had the following structure:
24 Answers
24
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How can I update the current line in a C# Windows Console App?
When building a Windows Console App in C#, is it possible to write to the console without having to extend a current line or go to a new line? For example, if I want to show a percentage representing how close a process is to completion, I'd just like to update the value on the same line as the cur...
Formatting a number with exactly two decimals in JavaScript
I have this line of code which rounds my numbers to two decimal places. But I get numbers like this: 10.8, 2.4, etc. These are not my idea of two decimal places so how I can improve the following?
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