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Loop through all nested dictionary values?
... yield inner_key, inner_value
else:
yield key, value
Test:
list(nested_dict_iter({'a':{'b':{'c':1, 'd':2},
'e':{'f':3, 'g':4}},
'h':{'i':5, 'j':6}}))
# output: [('g', 4), ('f', 3), ('c', 1), ('d', 2), ('i', 5), ('j', 6)]
I...
How do you use variables in a simple PostgreSQL script?
... get the last insert id:
DO $$
DECLARE lastid bigint;
BEGIN
INSERT INTO test (name) VALUES ('Test Name')
RETURNING id INTO lastid;
SELECT * FROM test WHERE id = lastid;
END $$;
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imp...
Python hashable dicts
...es, it is necessary to have the hash take the values into account. The fastest way to do that is:
class Hashabledict(dict):
def __hash__(self):
return hash((frozenset(self), frozenset(self.itervalues())))
This is quicker than frozenset(self.iteritems()) for two reasons. First, the f...
MySQL: selecting rows where a column is null
...
To search for column values that are NULL, you cannot use an expr = NULL test. The following statement returns no rows, because expr = NULL is never true for any expression
Solution
SELECT pid FROM planets WHERE userid IS NULL;
To test for NULL, use the IS NULL and IS NOT NULL operators.
opera...
How can I open multiple files using “with open” in Python?
...writelines(line)
EDIT:
I don't understand the reason of the downvote. I tested my code before publishing my answer, and it works as desired: It writes to all of outFile's, just as the question asks. No duplicate writing or failing to write. So I am really curious to know why my answer is consider...
Polymorphism in C++
...as the term is used in Computing Science - it helps to start from a simple test for and definition of it. Consider:
Type1 x;
Type2 y;
f(x);
f(y);
Here, f() is to perform some operation and is being given values x and y as inputs.
To exhibit polymorphism, f() must be able to ...
Pandas - Get first row value of a given column
...
To select the ith row, use iloc:
In [31]: df_test.iloc[0]
Out[31]:
ATime 1.2
X 2.0
Y 15.0
Z 2.0
Btime 1.2
C 12.0
D 25.0
E 12.0
Name: 0, dtype: float64
To select the ith value in the Btime column you could use:
In [...
How to implement a binary tree?
...rint(tree.getNodeValue())
printTree(tree.getRightChild())
# test tree
def testTree():
myTree = BinaryTree("Maud")
myTree.insertLeft("Bob")
myTree.insertRight("Tony")
myTree.insertRight("Steven")
printTree(myTree)
Read more about it Here:-This is a very simple im...
Convert SVG image to PNG with PHP
...n just place it in a loop and convert loads of SVGs,
import os
svgs = ('test1.svg', 'test2.svg', 'etc.svg')
for svg in svgs:
os.system('java -jar batik-rasterizer.jar -m image/jpeg -q 0.8 '+str(svg)+'.svg')
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How do I correctly clean up a Python object?
...t. Any class inheriting from Package should also do this (though I haven't tested that yet), so no metaclass should be required. Though I have found some pretty curious ways to use metaclasses in the past...
– Tobias Kienzler
Jan 17 '16 at 6:49
...