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Float vs Decimal in ActiveRecord
... you do this:
irb:001:0> "%.47f" % (1.0/10)
=> "0.10000000000000000555111512312578270211815834045" # not "0.1"!
whereas if you just do
irb:002:0> (1.0/10).to_s
=> "0.1" # the interprer rounds the number for you
So if you are dealing with small fractions, like compounding interests...
Rails hidden field undefined method 'merge' error
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edited Sep 15 '14 at 9:01
answered Jul 9 '11 at 19:10
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Python Matplotlib figure title overlaps axes label when using twiny
... that the default value is y=1 and the units is "axes fraction", i.e., y=0.5 means the title is in the middle of the axes, and y=0 means the title is just above the bottom of the axes.
– herrlich10
Oct 19 '17 at 12:31
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基于Windows平台的反Rootkit原理与实现 PDF - 文档下载 - 清泛网 - 专注C/C++及内核技术
........... ................................ ................................ 5
2.3 本软件开发基础 ................................ ................................ ................................ 6
2.4 程序界面拟合 ................................ ................................ ........
How to drop columns by name in a data frame
...exing or the subset function. For example :
R> df <- data.frame(x=1:5, y=2:6, z=3:7, u=4:8)
R> df
x y z u
1 1 2 3 4
2 2 3 4 5
3 3 4 5 6
4 4 5 6 7
5 5 6 7 8
Then you can use the which function and the - operator in column indexation :
R> df[ , -which(names(df) %in% c("z","u"))]
x ...
How exactly does a generator comprehension work?
...ach item out of the expression, one by one.
>>> my_list = [1, 3, 5, 9, 2, 6]
>>> filtered_list = [item for item in my_list if item > 3]
>>> print(filtered_list)
[5, 9, 6]
>>> len(filtered_list)
3
>>> # compare to generator expression
...
>>>...
How can I make pandas dataframe column headers all lowercase?
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5 Answers
5
Active
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How to get thread id from a thread pool?
I have a fixed thread pool that I submit tasks to (limited to 5 threads). How can I find out which one of those 5 threads executes my task (something like "thread #3 of 5 is doing this task")?
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Ruby Hash to array of values
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265
Also, a bit simpler....
>> hash = { "a"=>["a", "b", "c"], "b"=>["b", "c"] }
=> {...