大约有 44,900 项符合查询结果（耗时：0.0269秒） [XML]
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
>...
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...
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...
Algorithm for Determining Tic Tac Toe Game Over
...
22 Answers
22
Active
...
What do the numbers in a version typically represent (i.e. v1.9.0.1)?
...
28 Answers
28
Active
...
Convert numpy array to tuple
...
>>> arr = numpy.array(((2,2),(2,-2)))
>>> tuple(map(tuple, arr))
((2, 2), (2, -2))
share
|
improve this answer
|
...
Mod in Java produces negative numbers [duplicate]
When I calculate int i = -1 % 2 I get -1 in Java. In Python, I get 1 as the result of -1 % 2 .
What do I have to do to get the same behavior in Java with the modulo function?
...