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how to concatenate two dictionaries to create a new one in Python? [duplicate]
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Slowest and doesn't work in Python3: concatenate the items and call dict on the resulting list:
$ python -mtimeit -s'd1={1:2,3:4}; d2={5:6,7:9}; d3={10:8,13:22}' \
'd4 = dict(d1.items() + d2.items() + d3.items())'
100000 loops, best of 3: 4.93 usec per loop...
How to do a batch insert in MySQL
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304
From the MySQL manual
INSERT statements that use VALUES
syntax can insert multiple rows....
Simultaneously merge multiple data.frames in a list
...question was marked as a duplicate of this one so I answer here, using the 3 sample data frames below:
x <- data.frame(i = c("a","b","c"), j = 1:3, stringsAsFactors=FALSE)
y <- data.frame(i = c("b","c","d"), k = 4:6, stringsAsFactors=FALSE)
z <- data.frame(i = c("c","d","a"), l = 7:9, stri...
Rails 3 check if attribute changed
Need to check if a block of attributes has changed before update in Rails 3.
5 Answers
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What exactly is Arel in Rails 3.0?
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What exactly is Arel in Rails 3.0?
It's an object model for an algebra of relational query operators.
I understand that it is a replacement for ActiveRecord
No, it isn't. It's a replacement for hand-crafting SQL queries in strings. It is a common query...
Don't display pushd/popd stack across several bash scripts (quiet pushd/popd)
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3 Answers
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UINavigationController without navigation bar?
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edited Apr 9 at 15:30
iluvatar_GR
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answered Apr 23 '11 at ...
Django “login() takes exactly 1 argument (2 given)” error
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3 Answers
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How to alias a table in Laravel Eloquent queries (or using Query Builder)?
...B::table('really_long_table_name')->insert(['id' => null]);
// true
[3] > DB::table('really_long_table_name AS t')->select('t.id AS uid')->get();
// array(
// 0 => object(stdClass)(
// 'uid' => '1'
// )
// )
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Rails nested form with has_many :through, how to edit attributes of join model?
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3 Answers
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