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Append column to pandas dataframe
...
135
It seems in general you're just looking for a join:
> dat1 = pd.DataFrame({'dat1': [9,5]})...
Python creating a dictionary of lists
...s import defaultdict
>>> d = defaultdict(list)
>>> a = ['1', '2']
>>> for i in a:
... for j in range(int(i), int(i) + 2):
... d[j].append(i)
...
>>> d
defaultdict(<type 'list'>, {1: ['1'], 2: ['1', '2'], 3: ['2']})
>>> d.items()
[(1, ['1']), (...
jQuery map vs. each
...ion you can potentially waste a lot of memory.
For example:
var items = [1,2,3,4];
$.each(items, function() {
alert('this is ' + this);
});
var newItems = $.map(items, function(i) {
return i + 1;
});
// newItems is [2,3,4,5]
You can also use the map function to remove an item from an array...
How does numpy.histogram() work?
...
169
A bin is range that represents the width of a single bar of the histogram along the X-axis. Yo...
What's the difference between RANK() and DENSE_RANK() functions in oracle?
...
10 Answers
10
Active
...
Convert numpy array to tuple
...
161
>>> arr = numpy.array(((2,2),(2,-2)))
>>> tuple(map(tuple, arr))
((2, 2), (2...
Efficient way to apply multiple filters to pandas DataFrame or Series
...numpy) allow for boolean indexing, which will be much more efficient:
In [11]: df.loc[df['col1'] >= 1, 'col1']
Out[11]:
1 1
2 2
Name: col1
In [12]: df[df['col1'] >= 1]
Out[12]:
col1 col2
1 1 11
2 2 12
In [13]: df[(df['col1'] >= 1) & (df['col1'] <=1 )]
Out...
What's the difference between “mod” and “remainder”?
...
145
There is a difference between modulus and remainder. For example:
-21 mod 4 is 3 because -21 ...
Is it possible to install another version of Python to Virtualenv?
...
12 Answers
12
Active
...
PHP: merge two arrays while keeping keys instead of reindexing?
...
You can simply 'add' the arrays:
>> $a = array(1, 2, 3);
array (
0 => 1,
1 => 2,
2 => 3,
)
>> $b = array("a" => 1, "b" => 2, "c" => 3)
array (
'a' => 1,
'b' => 2,
'c' => 3,
)
>> $a + $b
array (
0 => 1,
1 => 2,
...