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Fastest way to replace NAs in a large data.table
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system.time(a_gdata = f_gdata(dt1))
user system elapsed
18.805 12.301 134.985
system.time(a_andrie = f_andrie(dt1))
Error: cannot allocate vector of size 305.2 Mb
Timing stopped at: 14.541 7.764 68.285
system.time(f_dowle(dt1))
user system elapsed
7.452 4.144 19.590 # EDIT h...
Update MongoDB field using value of another field
..."name": { "$concat": ["$firstName", " ", "$lastName"]}}}
]
)
MongoDB 3.4+
In 3.4+ you can use $addFields and the $out aggregation pipeline operators.
db.collection.aggregate(
[
{ "$addFields": {
"name": { "$concat": [ "$firstName", " ", "$lastName" ] }
}},
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Unicode与UTF-8互转(C语言实现) - C/C++ - 清泛网 - 专注C/C++及内核技术
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ASCII码一共规定了128个字符的编码, 比如空格"SPACE"是32(二进制00100000), 大写的
字母A是65(二进制01000001). 这128个符号(包括32个不能打印出来的控制符号), 只占用
了一个字节的后面7位, 最前面的1位统一规定为0.
1.2 非ASCII编码
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PyCharm shows unresolved references error for valid code
...Dmitry Trofimov
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How do I parse an ISO 8601-formatted date?
I need to parse RFC 3339 strings like "2008-09-03T20:56:35.450686Z" into Python's datetime type.
27 Answers
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Code equivalent to the 'let' keyword in chained LINQ extension method calls
...h = animalName.Length, animalName})
.Where(x=>x.nameLength > 3)
.OrderBy(x=>x.nameLength)
.Select(x=>x.animalName);
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Why always ./configure; make; make install; as 3 separate steps?
Every time you compile something from source, you go through the same 3 steps:
4 Answers
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jQuery Tips and Tricks
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edited Mar 23 '11 at 18:51
community wiki
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Replace tabs with spaces in vim
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393
IIRC, something like:
set tabstop=2 shiftwidth=2 expandtab
should do the trick. If you alre...
How to keep a Python script output window open?
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23 Answers
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