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Android: upgrading DB version and adding new table
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281
1. About onCreate() and onUpgrade()
onCreate(..) is called whenever the app is freshly instal...
Implement touch using Python?
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325
Looks like this is new as of Python 3.4 - pathlib.
from pathlib import Path
Path('path/to/fil...
What is a regular expression which will match a valid domain name without a subdomain?
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20 Answers
20
Active
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In Clojure, when should I use a vector over a list, and the other way around?
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112
Once again, it seems I've answered my own question by getting impatient and asking it in #clojur...
Lua简明教程 - 脚本技术 - 清泛IT论坛，有思想、有深度
...当你把他的源码下下来编译后，你会发现解释器居然不到200k，这是多么地变态啊（/bin/sh都要1M，MacOS平台），而且能和C语言非常好的互动。我很好奇得浏览了一下Lua解释器的源码，这可能是我看过最干净的C的源码了。我不想写...
Update value of a nested dictionary of varying depth
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24 Answers
24
Active
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Pandas conditional creation of a series/dataframe column
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print(df)
yields
Set Type color
0 Z A green
1 Z B green
2 X B red
3 Y C red
If you have more than two conditions then use np.select. For example, if you want color to be
yellow when (df['Set'] == 'Z') & (df['Type'] == 'A')
otherwise blue when (df['Set'] ...
How to use Bash to create a folder if it doesn't already exist?
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280
First, in bash "[" is just a command, which expects string "]" as a last argument, so the whit...
What is the difference between bottom-up and top-down?
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251
rev4: A very eloquent comment by user Sammaron has noted that, perhaps, this answer previou...
Looping through a hash, or using an array in PowerShell
...g the keys property. Here is an example how:
$hash = @{
a = 1
b = 2
c = 3
}
$hash.Keys | % { "key = $_ , value = " + $hash.Item($_) }
Output:
key = c , value = 3
key = a , value = 1
key = b , value = 2
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