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Ruby: Easiest Way to Filter Hash Keys?
...dated.
I'm adding an update here to help others avoid getting sidetracked by this answer like I did.
As the other answer mentions, Ruby >= 2.5 added the Hash#slice method which was previously only available in Rails.
Example:
> { one: 1, two: 2, three: 3 }.slice(:one, :two)
=> {:one=>...
What characters can be used for up/down triangle (arrow without stem) for display in HTML?
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Unicode arrows heads:
▲ - U+25B2 BLACK UP-POINTING TRIANGLE
▼ - U+25BC BLACK DOWN-POINTING TRIANGLE
▴ - U+25B4 SMALL BLACK UP-POINTING TRIANGLE
▾ - U+25BE SMALL BLACK DOWN-POINTING TRIANGLE
For ▲ and ▼ use ▲ and ▼ respect...
Creating a new column based on if-elif-else condition
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To formalize some of the approaches laid out above:
Create a function that operates on the rows of your dataframe like so:
def f(row):
if row['A'] == row['B']:
val = 0
elif row['A'] > row['B']:
val = 1
else:
val = -1
return va...
What is the difference between class and instance attributes?
Is there any meaningful distinction between:
5 Answers
5
...
How to list active / open connections in Oracle?
Is there any hidden table, system variable or something to show active connections in a given moment?
9 Answers
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Reshape three column data frame to matrix (“long” to “wide” format) [duplicate]
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There are many ways to do this. This answer starts with what is quickly becoming the standard method, but also includes older methods and various other methods from answers to similar questions scattered around this site.
tmp <- data.frame(x=gl(2,3, labels=letters[24:25]),
y...
PHP abstract properties
Is there any way to define abstract class properties in PHP?
9 Answers
9
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简单谈谈软件配置管理 - 项目管理 - 清泛网 - 专注C/C++及内核技术
...置项，建立和维护配置库；配置库管理；执行配置审计
b）配置控制委员会（CCB）：批准基线库的生成；评估和审核变更请求，并确保批准的更改得到实施.
c）QA：配置管理活动审查
2、配置管理的资源
a）配置库的服务器
b）...
Is Java's assertEquals method reliable?
...issues when comparing two Strings . It seems that String.equals() is a better approach. Well, I'm doing JUnit testing and my inclination is to use assertEquals(str1, str2) . Is this a reliable way to assert two Strings contain the same content? I would use assertTrue(str1.equals(str2)) , bu...
The ViewData item that has the key 'MY KEY' is of type 'System.String' but must be of type 'IEnumera
I am trying to populate a dropdown list from a database mapped with Linq-2-SQL, using ASP.NET MVC 2, and keep getting this error.
...