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Git pull without checkout?
I'm used to running git pull and other commands from within a branch I'm working on. But I have set up a development server that several people work on, so I don't want to have to switch branches when I do it. If I want to update an existing branch on the dev server from the github repository we a...
Check Whether a User Exists
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You can also check user by id command.
id -u name gives you the id of that user.
if the user doesn't exist, you got command return value ($?)1
And as other answers pointed out: if all you want is just to check if the user exists, use if with id directly, as i...
Nullable Foreign Key bad practice?
...hat bad practice or would you rather work with a link table between Orders and Customers? Although the relationship is 1 to n, a link table would make it n to n. On the other hand, with a link table, I don't have those NULLS anymore...
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passport.js RESTful auth
How does one handle authentication (local and Facebook, for example) using passport.js, through a RESTful API instead of through a web interface?
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How to write inline if statement for print?
...n Python 2.5)
expression_if_true if condition else expression_if_false
And note, that both print a and b = a are statements. Only the a part is an expression. So if you write
print a if b else 0
it means
print (a if b else 0)
and similarly when you write
x = a if b else 0
it means
x = ...
How does database indexing work? [closed]
...a section for data, a pointer to the location of the next node (or block), and both need not be stored contiguously.
Due to the fact that a number of records can only be sorted on one field, we can state that searching on a field that isn’t sorted requires a Linear Search which requires N/2 block...
What .NET collection provides the fastest search
...ection" depends on your specific data size, ordered-ness, cost-of-hashing, and search frequency.
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How to randomize (shuffle) a JavaScript array?
...github.com/coolaj86/knuth-shuffle
You can see a great visualization here (and the original post linked to this)
function shuffle(array) {
var currentIndex = array.length, temporaryValue, randomIndex;
// While there remain elements to shuffle...
while (0 !== currentIndex) {
//...
Why fragments, and when to use fragments instead of activities?
In Android API 11+, Google has released a new class called Fragment .
11 Answers
11
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Remove an entire column from a data.frame in R
...on't need drop argument cause it always return data.frame from data.frame. And I think this is much better way to localized columns (and only columns) in data.frame (and it's faster). Check: cars[-1] (one col data.frame) or better cars[-(1:2)]: data frame with 0 columns and 50 rows.
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