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Regex to check whether a string contains only numbers [duplicate]
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var reg = /^\d+$/;
should do it. The original matches anything that consists of exactly one digit.
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How to go to each directory and execute a command?
How do I write a bash script that goes through each directory inside a parent_directory and executes a command in each directory .
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What is the preferred syntax for defining enums in JavaScript?
What is the preferred syntax for defining enums in JavaScript? Something like:
48 Answers
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What should I name a table that maps two tables together? [closed]
...alidation
and naming things-- Phil Karlton
Coming up with a good name for a table that represents a many-to-many relationship makes the relationship easier to read and understand. Sometimes finding a great name is not trivial but usually it is worth to spend some time thinking about.
An example...
Git search for string in a single file's history
So if I have a file called foo.rb and it is giving me an error for a missing method called bar , so I want to search the history of foo.rb for the string bar to see if it was ever defined in the past.
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What's the difference between and , and ?
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They have the same effect on normal web browser rendering engines, but there is a fundamental difference between them.
As the author writes in a discussion list post:
Think of three different situations:
web browsers
blind people
mobile phones
"Bold...
Converting a double to an int in C#
...ed to 6.
...while the cast truncates:
When you convert from a double or float value to an integral type, the
value is truncated.
Update: See Jeppe Stig Nielsen's comment below for additional differences (which however do not come into play if score is a real number as is the case here).
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typeof !== “undefined” vs. != null
I often see JavaScript code which checks for undefined parameters etc. this way:
11 Answers
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Difference between .on('click') vs .click()
...erence is in usage patterns.
I would prefer .on over .click because the former can use less memory and work for dynamically added elements.
Consider the following html:
<html>
<button id="add">Add new</button>
<div id="container">
<button class="alert"&...
Should I use a data.frame or a matrix?
...d to be of different types (numeric/character/logical etc.). Matrices are for data of the same type.
Consequently, the choice matrix/data.frame is only problematic if you have data of the same type.
The answer depends on what you are going to do with the data in data.frame/matrix. If it is going ...