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Python idiom to return first item or None
...ython 2.4
def get_first(iterable, default=None):
if iterable:
for item in iterable:
return item
return default
Example:
x = get_first(get_first_list())
if x:
...
y = get_first(get_second_list())
if y:
...
Another option is to inline the above function:
for ...
How to convert index of a pandas dataframe into a column?
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keep in mind that you have to do this n times for every index you have (e.g. if you have two indices, then you have to do it twice)
– dval
May 19 '15 at 0:13
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Linux下安装项目管理工具Redmine - 开源 & Github - 清泛网 - 专注C/C++及内核技术
.... .bash_profile
2、RubyGems安装
# wget http://rubyforge.org/frs/download.php/60718/rubygems-1.3.5.tgz
# tar zxvf rubygems-1.3.5.tgz
# cd rubygems-1.3.5
# ruby setup.rb
3、Rake安装
# gem install rake //直接使用gem命令安装rake.
//也可...
What does auto do in margin:0 auto?
...margin-top:0;
margin-bottom:0;
margin-left:auto;
margin-right:auto;
Therefore, to give you an example, if the parent is 100px and the child is 50px, then the auto property will determine that there's 50px of free space to share between margin-left and margin-right:
var freeSpace = 100 - 50;
var e...
Set time part of DateTime in ruby
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Don't forget: now = DateTime.now
– Abel
Nov 4 '15 at 19:30
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How accurately should I store latitude and longitude?
...ke these worst case errors. Or to be pedantic, these are worst case errors for using lat/lon at sea level. At an elevation of 6,378 m, the error increases by 0.1%.
– Scott B
Mar 13 '14 at 23:08
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getViewTypeCount and getItemViewType methods of ArrayAdapter
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These handle the case where you want different types of view for different rows. For instance, in a contacts application you may want even rows to have pictures on the left side and odd rows to have pictures on the right. In that case, you would use:
@Override
public int getViewTypeCo...
How to get the first element of an array?
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Thanks for the historic screenshot :)
– Boern
Jun 29 at 13:39
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SQL query return data from multiple tables
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Joining two or more tables using an inner join (See the wikipedia entry for additional info)
How to use a union query
Left and Right Outer Joins (this stackOverflow answer is excellent to describe types of joins)
Intersect queries (and how to reproduce them if your database doesn't support them) ...
plot a circle with pyplot
surprisingly I didn't find a straight-forward description on how to draw a circle with matplotlib.pyplot (please no pylab) taking as input center (x,y) and radius r. I tried some variants of this:
...