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how does multiplication differ for NumPy Matrix vs Array classes?
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Neil G
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answered Oct 8 '10 at 16:49
Joe KingtonJoe Ki...
Fastest way to check if a string matches a regexp in ruby?
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104
Starting with Ruby 2.4.0, you may use RegExp#match?:
pattern.match?(string)
Regexp#match? is...
Simple regular expression for a decimal with a precision of 2
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408
Valid regex tokens vary by implementation. A generic form is:
[0-9]+(\.[0-9][0-9]?)?
More co...
Find MongoDB records where array field is not empty
... the key, you can use:
ME.find({ pictures: { $exists: true, $not: {$size: 0} } })
MongoDB don't use indexes if $size is involved, so here is a better solution:
ME.find({ pictures: { $exists: true, $ne: [] } })
Since MongoDB 2.6 release, you can compare with the operator $gt but could lead to u...
Determine the data types of a data frame's columns
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220
Your best bet to start is to use ?str(). To explore some examples, let's make some data:
set...
How to use a decimal range() step value?
Is there a way to step between 0 and 1 by 0.1?
33 Answers
33
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How to slice an array in Bash
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answered Aug 26 '09 at 17:10
Paused until further notice.Paused until further notice.
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How to iterate for loop in reverse order in swift?
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With Swift 2.0 it is now: 5.stride(to: 1, by: -1) or 5.stride(through: 1, by: -1)
– Binarian
Sep 21 '15 at 9:23
6
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Split (explode) pandas dataframe string entry to separate rows
... for _, row in a.iterrows()]).reset_index()
Out[55]:
index 0
0 a 1
1 b 1
2 c 1
3 d 2
4 e 2
5 f 2
Then you just have to rename the columns
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impr...
浅析为什么char类型的范围是 -128~+127 - C/C++ - 清泛网 - 专注C/C++及内核技术
...，全部位都表示数值，比如 char型，8位，用二进制表示为0000 0000 ~ 1111 1111
1111 1111 最大即为十进制255,所以 unsigned char 的范围为0~ 255，在这里普及一下2进制转十进制的方法， 二进制每一位的数值乘以它的位权(2^(n-1),n为自右向左...