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Remove duplicated rows using dplyr
...(0:1, 10, replace = T),
y = sample(0:1, 10, replace = T),
z = 1:10
)
One approach would be to group, and then only keep the first row:
df %>% group_by(x, y) %>% filter(row_number(z) == 1)
## Source: local data frame [3 x 3]
## Groups: x, y
##
## x y z
## 1 0 1 1
## 2 1 0 2
## 3 1 1 ...
When should I use jQuery deferred's “then” method and when should I use the “pipe” method?
...hen the deferred object is resolved or rejected. It is the same as using .done() or .fail().
You'd use .pipe() to (pre)filter the result somehow. The return value of a callback to .pipe() will be passed as argument to the done and fail callbacks. It can also return another deferred object and the f...
WatiN or Selenium? [closed]
...t coding some automated tests of our presentation soon. It seems that everyone recommends WatiN and Selenium . Which do you prefer for automated testing of ASP.NET web forms? Which of these products work better for you?
...
In Python, how do I indicate I'm overriding a method?
...ainly this happens after (again) seeing the same bug in our code base: Someone has forgotten some "interface" implementing class while renaming a method in the "interface"..
Well Python ain't Java but Python has power -- and explicit is better than implicit -- and there are real concrete cases in t...
Simple way to encode a string according to a password?
...d party libraries. I'd recommend something like the Vigenere cipher. It is one of the strongest of the simple ancient ciphers.
Vigenère cipher
It's quick and easy to implement. Something like:
import base64
def encode(key, string):
encoded_chars = []
for i in xrange(len(string)):
...
How do I prevent commands from showing up in Bash history?
...xport HISTIGNORE=' *'. Then just begin any command you want to ignore with one space.
$ ls # goes in history
$ ls # does not
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Convert Newtonsoft.Json.Linq.JArray to a list of specific object type
...le if the array has a null field? This time i get the error JsonSerializationException. I want the data and i want it remain null for any null data.
– Ensar Turkoglu
Apr 19 '17 at 11:09
...
Set database from SINGLE USER mode to MULTI USER
...ome innocent system database like master or tempdb in the drop-down in the one window you have left.
– user
Jan 19 '17 at 15:29
...
Why can't I define a default constructor for a struct in .NET?
... goes.)
EDIT: To use your example, what would you want to happen when someone did:
Rational[] fractions = new Rational[1000];
Should it run through your constructor 1000 times?
If not, we end up with 1000 invalid rationals
If it does, then we've potentially wasted a load of work if we're about...
Can I call memcpy() and memmove() with “number of bytes” set to zero?
...ent of an array? Such a pointer could not be legitimately deferenced, but one could safely do some other pointer-ish things like subtract one from it.
– supercat
Nov 20 '11 at 22:19
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