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Python - Create a list with initial capacity
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def doAppend( size=10000 ):
result = []
for i in range(size):
message= "some unique object %d" % ( i, )
result.append(message)
return result
def doAllocate( size=10000 ):
result=size*[None]
for i in range(size):
message= "some unique obj...
How to use range-based for() loop with std::map?
The common example for C++11 range-based for() loops is always something simple like this:
5 Answers
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Deleting DataFrame row in Pandas based on column value
...sking:
In [56]: df
Out[56]:
line_date daysago line_race rating raw wrating
0 2007-03-31 62 11 56 1.000 56.000
1 2007-03-10 83 11 67 1.000 67.000
2 2007-02-10 111 9 66 1.000 66.000
3 2007-01-13 139 10 ...
What is the difference between tinyint, smallint, mediumint, bigint and int in MySQL?
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They take up different amounts of space and they have different ranges of acceptable values.
Here are the sizes and ranges of values for SQL Server, other RDBMSes have similar documentation:
MySQL
Postgres
Oracle (they just have a NUMBER datatype really)
DB2
Turns out they all use th...
List comprehension vs map
...tage of map when using exactly the same function:
$ python -mtimeit -s'xs=range(10)' 'map(hex, xs)'
100000 loops, best of 3: 4.86 usec per loop
$ python -mtimeit -s'xs=range(10)' '[hex(x) for x in xs]'
100000 loops, best of 3: 5.58 usec per loop
An example of how performance comparison gets compl...
Is it possible to use 'else' in a list comprehension? [duplicate]
...) if index in ords_to_keep else replace_with
for index in xrange(15))
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Remove all values within one list from another list? [duplicate]
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>>> a = range(1, 10)
>>> [x for x in a if x not in [2, 3, 7]]
[1, 4, 5, 6, 8, 9]
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Types in MySQL: BigInt(20) vs Int(20)
... It's a hint for display width. It has nothing to do with storage, nor the range of values that column will accept.
Practically, it affects only the ZEROFILL option:
CREATE TABLE foo ( bar INT(20) ZEROFILL );
INSERT INTO foo (bar) VALUES (1234);
SELECT bar from foo;
+----------------------+
| b...
How can I install Apache Ant on Mac OS X?
...mmand in a terminal window to install brew:
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
It's a medium sized download which took me 10min to download and install. Just follow the process which involves installing various components. If you already have...
Why (0-6) is -6 = False? [duplicate]
...tialization in a block of integer objects we saw above. The small integers range is from -5 to 256. Many Python programs spend a lot of time using integers in that range so this is a smart decision.
This is only an implementation detail of CPython and you shouldn't rely on this. For instance, PyPy...