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Can you supply arguments to the map(&:method) syntax in Ruby?
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141
You can create a simple patch on Symbol like this:
class Symbol
def with(*args, &block)...
How does zip(*[iter(s)]*n) work in Python?
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111
iter() is an iterator over a sequence. [x] * n produces a list containing n quantity of x, i.e...
Replace all 0 values to NA
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Replacing all zeroes to NA:
df[df == 0] <- NA
Explanation
1. It is not NULL what you should want to replace zeroes with. As it says in ?'NULL',
NULL represents the null object in R
which is unique and, I guess, can be seen as the most uninformative and empty object.1 Then it b...
How to use the 'sweep' function
...nd use in the operation defined by FUN.
For instance, if you want to add 1 to the 1st row, 2 to the 2nd, etc. of the matrix you defined, you will do:
sweep (M, 1, c(1: 4), "+")
I frankly did not understand the definition in the R documentation either, I just learned by looking up examples.
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What is the fastest method for selecting descendant elements in jQuery?
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Method 1 and method 2 are identical with the only difference is that method 1 needs to parse the scope passed and translate it to a call to $parent.find(".child").show();.
Method 4 and Method 5 both need to parse the selector and ...
Numbering rows within groups in a data frame
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edited Mar 14 '17 at 22:06
Frank
62.4k88 gold badges8181 silver badges157157 bronze badges
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Pass a data.frame column name to a function
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109
You can just use the column name directly:
df <- data.frame(A=1:10, B=2:11, C=3:12)
fun1 &...
Pandas get topmost n records within each group
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195
Did you try df.groupby('id').head(2)
Ouput generated:
>>> df.groupby('id').head(2)...
php中json_decode()和json_encode()的使用方法 - 更多技术 - 清泛网 - 专注C/C++及内核技术
php中json_decode()和json_encode()的使用方法1.json_decode()json_decode(PHP 5 >= 5.2.0, PECL json >= 1.2.0)json_decode — 对 JSON 格式的字符串进行编码说明mixed jso...1.json_decode()
(PHP 5 >= 5.2.0, PECL json >= 1.2.0)
对 JSON 格式的字符串进行编码
说明：
mix...