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What's the fastest way to merge/join data.frames in R?
...s for duplicate keys. (continued after code)
DF1 = data.frame(a = c(1, 1, 2, 2), b = 1:4)
DF2 = data.frame(b = c(1, 2, 3, 3, 4), c = letters[1:5])
merge(DF1, DF2)
b a c
1 1 1 a
2 2 1 b
3 3 2 c
4 3 2 d
5 4 2 e
DF1$c = DF2$c[match(DF1$b, DF2$b)]
DF1$c
[1] a b c e
Levels: a b c d e
>...
[] and {} vs list() and dict(), which is better?
...>>> from timeit import timeit
>>> timeit("[]")
0.040084982867934334
>>> timeit("list()")
0.17704233359267718
>>> timeit("{}")
0.033620194745424214
>>> timeit("dict()")
0.1821558326547077
and for non-empty:
>>> timeit("[1,2,3]")
0.2431630277033...
How to upgrade Git on Windows to the latest version?
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Since Git 2.16.1(2) you can use
C:\> git update-git-for-windows
In versions between 2.14.2 and 2.16.1, the command was
C:\> git update
(It was later renamed to avoid confusion with updating the local repository, e.g. like s...
Is there a ceiling equivalent of // operator in Python?
... |
edited Sep 14 at 21:47
Machavity♦
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a...
How to remove specific elements in a numpy array
...index)
For your specific question:
import numpy as np
a = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9])
index = [2, 3, 6]
new_a = np.delete(a, index)
print(new_a) #Prints `[1, 2, 5, 6, 8, 9]`
Note that numpy.delete() returns a new array since array scalars are immutable, similar to strings in Python...
Algorithm for Determining Tic Tac Toe Game Over
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22 Answers
22
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Convert base-2 binary number string to int
I'd simply like to convert a base-2 binary number string into an int, something like this:
8 Answers
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代码块超过1.2w编译apk报错问题 - App Inventor 2 中文网 - 清泛IT社区，为创新赋能！
报错信息：
3月 04, 2025 9:50:11 上午 com.google.appengine.tools.development.ApiProxyLocalImpl log
严重: javax.servlet.ServletContext log: Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract long com.google.appinv...