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How to group dataframe rows into list in pandas groupby?
...alues('a').values.T
ukeys, index = np.unique(keys, True)
arrays = np.split(values, index[1:])
df2 = pd.DataFrame({'a':ukeys, 'b':[list(a) for a in arrays]})
return df2
Tests:
In [301]: %timeit f(df)
1000 loops, best of 3: 1.64 ms per loop
In [302]: %timeit df....
How to “pretty” format JSON output in Ruby on Rails
...t into later versions of JSON. For example:
require 'json'
my_object = { :array => [1, 2, 3, { :sample => "hash"} ], :foo => "bar" }
puts JSON.pretty_generate(my_object)
Which gets you:
{
"array": [
1,
2,
3,
{
"sample": "hash"
}
],
"foo": "bar"
}
...
Running script upon login mac [closed]
...ginscript</string>
<key>ProgramArguments</key>
<array><string>/path/to/executable/script.sh</string></array>
<key>RunAtLoad</key>
<true/>
</dict>
</plist>
Replace the <string> after the Program key with your ...
Java switch statement: Constant expression required, but it IS constant
...oesn't include any form of method or lambda calls, new, .class. .length or array subscripting. Furthermore, any use of array values, enum values, values of primitive wrapper types, boxing and unboxing are all excluded because of a).
...
How do cache lines work?
...ory, L3 notifies the L2 that the line is ready, and copies it into its own array.
– Peter Cordes
Sep 1 '16 at 0:47
2
...
Difference between size_t and unsigned int?
...chosen so that it could store the maximum size
of a theoretically possible array of any type. On a
32-bit system size_t will take 32 bits, on a 64-
bit one 64 bits. In other words, a variable of
size_t type can safely store a pointer. The
exception is pointers to class functions but this
is a specia...
Passing an integer by reference in Python
...
A numpy single-element array is mutable and yet for most purposes, it can be evaluated as if it was a numerical python variable. Therefore, it's a more convenient by-reference number container than a single-element list.
import numpy as np
...
How to copy a file to a remote server in Python using SCP or SSH?
...ng subprocess.Popen is the Right Thing. Passing it a string rather than an array (and using shell=True) is the Wrong Thing, as it means filenames with spaces don't work correctly.
– Charles Duffy
Oct 15 '08 at 12:07
...
Advantages of using prototype, vs defining methods straight in the constructor? [duplicate]
...e the prototype method
Class.prototype.calc = function () {
var args = Array.prototype.slice.apply(arguments),
res = 0, c;
while (c = args.shift())
res += c;
return res;
}
// Test the calc method:
console.log(ins1.calc(1,1,1), ins2.calc(1,1,1));
// -> 3, 3
Notice...
How do I get a substring of a string in Python?
...r completeness as nobody else has mentioned it. The third parameter to an array slice is a step. So reversing a string is as simple as:
some_string[::-1]
Or selecting alternate characters would be:
"H-e-l-l-o- -W-o-r-l-d"[::2] # outputs "Hello World"
The ability to step forwards and backward...