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Why does the order of the loops affect performance when iterating over a 2D array?
...y location in the array: x[i][j]. Here's a bit of insight why:
You have a 2-dimensional array, but memory in the computer is inherently 1-dimensional. So while you imagine your array like this:
0,0 | 0,1 | 0,2 | 0,3
----+-----+-----+----
1,0 | 1,1 | 1,2 | 1,3
----+-----+-----+----
2,0 | 2,1 | 2,2 ...
How can I exclude all “permission denied” messages from “find”?
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Note:
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Find the max of two or more columns with pandas
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2 Answers
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Active
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How to deal with SettingWithCopyWarning in Pandas?
...copy. [see GH5390 and GH5597 for background discussion.]
df[df['A'] > 2]['B'] = new_val # new_val not set in df
The warning offers a suggestion to rewrite as follows:
df.loc[df['A'] > 2, 'B'] = new_val
However, this doesn't fit your usage, which is equivalent to:
df = df[df['A'] > ...
How can I debug git/git-shell related problems?
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217
For even more verbose output use following:
GIT_CURL_VERBOSE=1 GIT_TRACE=1 git pull origin ma...
Can dplyr package be used for conditional mutating?
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220
Use ifelse
df %>%
mutate(g = ifelse(a == 2 | a == 5 | a == 7 | (a == 1 & b == 4), 2,
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Python creating a dictionary of lists
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286
You can use defaultdict:
>>> from collections import defaultdict
>>> d = de...
Ruby 2.0.0p0 IRB warning: “DL is deprecated, please use Fiddle”
...ions of Ruby, removed all of my gems
(including Rails), and installed Ruby 2.0. In other words, a totally clean re-install. Upon starting IRB, I received this message:
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WinDBG用法详解 PDF - 文档下载 - 清泛网 - 专注C/C++及内核技术
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