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How do I delete rows in a data frame?
... data may change in the future. A general principle of a data.frame or database tables is that the order of the rows should not matter. If the order does matter, this should be encoded in an actual variable in the data.frame.
For example, imagine you imported a dataset and deleted rows by numeric...
Revert changes to a file in a commit
...2:
aaa333 Good commit
aaa222 Problem commit containing badfile.txt
aaa111 Base commit
Rebase on the base commit, amend the problem commit, & continue.
1) Start interactive rebase:
git rebase -i aaa111
2) Mark the problem commit for edit in the editor by changing pick to e (for edit):
e a...
How to do joins in LINQ on multiple fields in single join
...es, anyway), and indeed that's what you've said you want to express anyway based on your original query.
If you don't like the version with the anonymous type for some specific reason, you should explain that reason.
If you want to do something other than what you originally asked for, please give...
How to find which rspec test is taking so long
...s.
For RSpec 1, you can use --format o with spec command. It shows a text-based progress bar with profiling of 10 slowest examples. For more details see this.
rspec --profile -- path/to/file/spec.rb
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Can an Android NFC phone act as an NFC tag?
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This is outdated. Android 4.4 has host-based card emulation, which allows precisely this: developer.android.com/guide/topics/connectivity/nfc/hce.html
– Trevor Johns
Jan 26 '14 at 18:42
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How to reverse a string in Go?
...y.golang.org/p/sBgZAV7gCb, the combining character is not swapped with its base.
– chowey
Jan 17 '15 at 2:59
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How do I calculate the date six months from the current date using the datetime Python module?
...f the answers on this page do not.
You need to first shift the months from base 1 (ie Jan = 1) to base 0 (ie Jan = 0) before using modulus ( % ) or integer division ( // ), otherwise November (11) plus 1 month gives you 12, which when finding the remainder ( 12 % 12 ) gives 0.
(And dont suggest "(m...
Applying a function to every row of a table using dplyr?
...a good handle on this topic.
The most straightforward way I have found is based on one of Hadley's examples using pmap:
iris %>%
mutate(Max.Len= purrr::pmap_dbl(list(Sepal.Length, Petal.Length), max))
Using this approach, you can give an arbitrary number of arguments to the function (.f) ...
Create Directory When Writing To File In Node.js
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This should use statSync instead of existsSync, based on stackoverflow.com/questions/4482686/…
– GavinR
Feb 3 '16 at 22:18
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Difference between OperationCanceledException and TaskCanceledException?
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OperationCanceledException is simply the base class for TaskCanceledException - so if you catch the former, you'll still catch the latter.
Some operations on concurrent collections throw just OperationCanceledException, as there aren't any actual tasks involved (at...