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Best way to extract a subvector from a vector?
... +1, also it's O(Y-X), which is less than or equal to O(N) (and in his example much less)
– orip
Jan 7 '09 at 21:53
78
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Find column whose name contains a specific string
I have a dataframe with column names, and I want to find the one that contains a certain string, but does not exactly match it. I'm searching for 'spike' in column names like 'spike-2' , 'hey spike' , 'spiked-in' (the 'spike' part is always continuous).
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Callback functions in C++
In C++, when and how do you use a callback function?
10 Answers
10
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Using try vs if in python
...er LBYL style ("look before you leap"). To me, it's a matter of efficiency and readability.
In your example (say that instead of returning a list or an empty string, the function were to return a list or None), if you expect that 99 % of the time result will actually contain something iterable, I'd...
Getting the closest string match
I need a way to compare multiple strings to a test string and return the string that closely resembles it:
12 Answers
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Convert data.frame column to a vector?
...a frame is a list. When you subset a data frame using the name of a column and [, what you're getting is a sublist (or a sub data frame). If you want the actual atomic column, you could use [[, or somewhat confusingly (to me) you could do aframe[,2] which returns a vector, not a sublist.
So try run...
Why does range(start, end) not include end?
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You explain that range(x) should start with 0 and x will be the "length of the range". OK. But you didn't explain why range(x,y) should start with x and end with y-1. If the programmer wants a for-loop with i ranging from 1 to 3, he has to explicitly add 1. Is this reall...
How to count number of files in each directory?
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Assuming you have GNU find, let it find the directories and let bash do the rest:
find . -type d -print0 | while read -d '' -r dir; do
files=("$dir"/*)
printf "%5d files in directory %s\n" "${#files[@]}" "$dir"
done
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Any way to clear python's IDLE window?
...n console, but I do not know if they are the same. I tried system("clear") and it didn't work here.
25 Answers
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Pad a string with leading zeros so it's 3 characters long in SQL Server 2008
...t;= 3, if you want something larger you need to change the string constant and the two integer constants to the width needed. eg '0000' and VARCHAR(4)),4
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