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Cleaning `Inf` values from an R dataframe
...ame]])), j = .name,value =NA)))
Or using column numbers (possibly faster if there are a lot of columns):
for (j in 1:ncol(DT)) set(DT, which(is.infinite(DT[[j]])), j, NA)
Timings
# some `big(ish)` data
dat <- data.frame(a = rep(c(1,Inf), 1e6), b = rep(c(Inf,2), 1e6),
c = ...
MySQL, Check if a column exists in a table with SQL
I am trying to write a query that will check if a specific table in MySQL has a specific column, and if not — create it. Otherwise do nothing. This is really an easy procedure in any enterprise-class database, yet MySQL seems to be an exception.
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Build tree array from flat array in javascript
... has :
id : a unique id,
parentId : the id of the parent node (which is 0 if the node is a root of the tree)
level : the level of depth in the tree
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handlerbars.js check if list is empty
Is there a way in Handlebars.js templating to check if the collection or list is null or empty, before going and iterating through the list/collection?
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Return a value if no rows are found in Microsoft tSQL
Using a Microsoft version of SQL, here's my simple query. If I query a record that doesn't exist then I will get nothing returned. I'd prefer that false (0) is returned in that scenario. Looking for the simplest method to account for no records.
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Checking if a variable is an integer
Does Rails 3 or Ruby have a built-in way to check if a variable is an integer?
11 Answers
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Is “else if” a single keyword?
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They are not a single keyword if we go to the draft C++ standard section 2.12 Keywords table 4 lists both if and else separately and there is no else if keyword. We can find a more accessible list of C++ keywords by going to cppreferences section on keyw...
How do I iterate through each element in an n-dimensional matrix in MATLAB?
...dx = 1:numel(array)
element = array(idx)
....
end
This is useful if you don't need to know what i,j,k, you are at. However, if you don't need to know what index you are at, you are probably better off using arrayfun()
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Java String - See if a string contains only numbers and not letters
...ication, and it changes from numbers to letters and such. I have a simple if statement to see if it contains letters or numbers but, something isn't quite working correctly. Here is a snippet.
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Javascript shorthand ternary operator
...ber || 1;
Something like that what you're looking for, where it defaults if undefined?
var foo = bar || 1; // 1
var bar = 2;
foo = bar || 1; // 2
By the way, this works for a lot of scenarios, including objects:
var foo = bar || {}; // secure an object is assigned when bar is absent
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