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Base64: What is the worst possible increase in space usage?
...the size of the base-64 representation of a string of size n is:
ceil(n / 3) * 4
So, for a 16kB array, the base-64 representation will be ceil(16*1024/3)*4 = 21848 bytes long ~= 21.8kB.
A rough approximation would be that the size of the data is increased to 4/3 of the original.
...
How to randomly select an item from a list?
..., 'horse', 'staple']
print(secrets.choice(foo))
secrets is new in Python 3.6, on older versions of Python you can use the random.SystemRandom class:
import random
secure_random = random.SystemRandom()
print(secure_random.choice(foo))
...
What does this square bracket and parenthesis bracket notation mean [first1,last1)?
...
234
A bracket means that end of the range is inclusive -- it includes the element listed. A parenth...
Stacked Tabs in Bootstrap 3
...plement left-aligned stacked tabs using the Tab jquery plugin in Bootstrap 3 where tabs are rendered vertically to the left of tab content, rather than on top. When I try the following;
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Difference between map, applymap and apply methods in Pandas
...
Straight from Wes McKinney's Python for Data Analysis book, pg. 132 (I highly recommended this book):
Another frequent operation is applying a function on 1D arrays to each column or row. DataFrame’s apply method does exactly this:
In [116]: frame = DataFrame(np.random.randn(4, 3),...
ros 基本调试 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...端口
2.1.1.1虚拟机
2.1.1.2真实电脑——物理串行线
2.1.1.3基于freebsd的串行终端
2.1.2将调试文字输出到文件
2.1.3将调试文字输出到屏幕
2.1.4修改波特率（数据传输速率）
2.2KDBG
2.3GDB
2.4WINDBG
3.生成更多输出
3.1编译时开启verbosi...
Pass a variable into a partial, rails 3?
...
237
Try this:
<% @posts.each do |post| %>
<%= render 'middle', :post => post %>
&...
Return two and more values from a method
...
def sumdiff(x, y)
return x+y, x-y
end
#=> nil
sumdiff(3, 4)
#=> [7, -1]
a = sumdiff(3,4)
#=> [7, -1]
a
#=> [7, -1]
a,b=sumdiff(3,4)
#=> [7, -1]
a
#=> 7
b
#=> -1
a,b,c=sumdiff(3,4)
#=> [7, -1]
a
#=> 7
b
#=> -1
c
#=> nil
...
how to convert array values from string to int?
...
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edited Apr 23 '19 at 10:46
Rahul
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