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No secret option provided to Rack::Session::Cookie warning?
I am running Rails 3.2.3, Ruby 1.9 under Fedora 17. I get this warning, when I run rails s , and how do I fix?
7 Answers
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Pandas: create two new columns in a dataframe with values calculated from a pre-existing column
... from pandas import *
In [2]: def calculate(x):
...: return x*2, x*3
...:
In [3]: df = DataFrame({'a': [1,2,3], 'b': [2,3,4]})
In [4]: df
Out[4]:
a b
0 1 2
1 2 3
2 3 4
In [5]: df["A1"], df["A2"] = zip(*df["a"].map(calculate))
In [6]: df
Out[6]:
a b A1 A2
0 1 2 2...
How to use background thread in swift?
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Swift 3.0+
A lot has been modernized in Swift 3.0. Running something on the background thread looks like this:
DispatchQueue.global(qos: .background).async {
print("This is run on the background queue")
DispatchQueue.mai...
How to iterate a loop with index and element in Swift
...
Yes. As of Swift 3.0, if you need the index for each element along with its value, you can use the enumerated() method to iterate over the array. It returns a sequence of pairs composed of the index and the value for each item in the array. F...
Clojure: cons (seq) vs. conj (list)
...ments to insert into a collection, while cons takes just one:
(conj '(1 2 3) 4 5 6)
; => (6 5 4 1 2 3)
(cons 4 5 6 '(1 2 3))
; => IllegalArgumentException due to wrong arity
Another difference is in the class of the return value:
(class (conj '(1 2 3) 4))
; => clojure.lang.PersistentLi...
Removing duplicates from a list of lists
...
>>> k = [[1, 2], [4], [5, 6, 2], [1, 2], [3], [4]]
>>> import itertools
>>> k.sort()
>>> list(k for k,_ in itertools.groupby(k))
[[1, 2], [3], [4], [5, 6, 2]]
itertools often offers the fastest and most powerful solutions to this kind of ...
How can I remove 3 characters at the end of a string in php?
How can I remove 3 characters at the end of a string in php? "abcabcabc" would become "abcabc"!
3 Answers
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Move an array element from one array position to another
...
31 Answers
31
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In Ruby, is there an Array method that combines 'select' and 'map'?
... as a postfix if. compact gets rid of the nils.
jruby-1.5.0 > [1,1,1,2,3,4].map{|n| n*3 if n==1}
=> [3, 3, 3, nil, nil, nil]
jruby-1.5.0 > [1,1,1,2,3,4].map{|n| n*3 if n==1}.compact
=> [3, 3, 3]
share...
Is it possible to install another version of Python to Virtualenv?
...rce/v/virtualenv/virtualenv-1.5.2.tar.gz#md5=fbcefbd8520bb64bc24a560c6019a73c
tar -zxvf virtualenv-1.5.2.tar.gz
cd virtualenv-1.5.2/
~/.localpython/bin/python setup.py install
3) Create a virtualenv using your local python
virtualenv docs
mkdir /home/${USER}/virtualenvs
cd /home/${USER}/virtualen...