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How can you determine how much disk space a particular MySQL table is taking up?
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For a table mydb.mytable run this for:
BYTES
SELECT (data_length+index_length) tablesize
FROM information_schema.tables
WHERE table_schema='mydb' and table_name='mytable';
KILOBYTES
SELECT (data_length+index_length)/power(1024,1) tablesize_kb
FROM information_schema.tables
WHERE table_s...
B-Tree vs Hash Table
In MySQL, an index type is a b-tree, and access an element in a b-tree is in logarithmic amortized time O(log(n)) .
5 Answ...
Creating a Pandas DataFrame from a Numpy array: How do I specify the index column and column headers
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You need to specify data, index and columns to DataFrame constructor, as in:
>>> pd.DataFrame(data=data[1:,1:], # values
... index=data[1:,0], # 1st column as index
... columns=data[0,1:]) # 1st row as the co...
When and why are database joins expensive?
... working set. Joins involving properly selected keys with correctly set up indexes are cheap, not expensive, because they allow significant pruning of the result before the rows are materialised.
Materialising the result involves bulk disk reads which are the most expensive aspect of the exercise ...
How do I strip all spaces out of a string in PHP? [duplicate]
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Newbie question out of interest: What is the difference between space and whitespace? Isn't it the same?
– Kai Noack
Sep 12 '13 at 10:50
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Random row selection in Pandas dataframe
...like this?
import random
def some(x, n):
return x.ix[random.sample(x.index, n)]
Note: As of Pandas v0.20.0, ix has been deprecated in favour of loc for label based indexing.
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improve ...
Remap values in pandas column with a dict
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map also works on an index where I couldn't figure out a way to do that with replace
– Max Ghenis
Mar 15 '19 at 16:42
1
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How to validate inputs dynamically created using ng-repeat, ng-show (angular)
...s the same name as the cell above and below it. I attempted to use the {{$index}} value to name the inputs, but despite the string literals in HTML appearing correct, it is now working.
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SQL - many-to-many table primary key
...r col1 and col2 values in the referenced tables are unique) and a separate index on (col2,col1) will catch those cases where the opposite order would execute faster. The surrogate is a waste of space.
You won't need indexes on the individual columns since the table should only ever be used to join ...
Google Maps API - Get Coordinates of address
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@n00b: I initially mis-read your question. You're looking for Geocoding, not Reverse Geocoding. Nevertheless, you can still do it with the Google Web Services API.
– Daniel Vassallo
Sep 6 '10 at 16:41
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