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How to add column if not exists on PostgreSQL?
...statement:
DO $$
BEGIN
BEGIN
ALTER TABLE <table_name> ADD COLUMN <column_name> <column_type>;
EXCEPTION
WHEN duplicate_column THEN RAISE NOTICE 'column <column_name> already exists in <table_name>.';
END;
END;
$$
...
Checking a Python module version at runtime
...rmation for the module (usually something like module.VERSION or module.__version__ ), however some do not.
7 Answers
...
Measuring elapsed time with the Time module
...
start_time = time.time()
# your code
elapsed_time = time.time() - start_time
You can also write simple decorator to simplify measurement of execution time of various functions:
import time
from functools import wraps
PROF_DATA...
How do you test that a Python function throws an exception?
...t ahold of the actual Exception object thrown:
import unittest
def broken_function():
raise Exception('This is broken')
class MyTestCase(unittest.TestCase):
def test(self):
with self.assertRaises(Exception) as context:
broken_function()
self.assertTrue('This i...
Why does 'continue' behave like 'break' in a Foreach-Object?
..., it simulates the continue in a loop.
1..100 | ForEach-Object {
if ($_ % 7 -ne 0 ) { return }
Write-Host "$($_) is a multiple of 7"
}
There is a gotcha to be kept in mind when refactoring. Sometimes one wants to convert a foreach statement block into a pipeline with a ForEach-Object cmdl...
Getting distance between two points based on latitude/longitude
...4, and is implemented in geopy. For example,
import geopy.distance
coords_1 = (52.2296756, 21.0122287)
coords_2 = (52.406374, 16.9251681)
print geopy.distance.vincenty(coords_1, coords_2).km
will print the distance of 279.352901604 kilometers using the default ellipsoid WGS-84. (You can also ch...
How to set or change the default Java (JDK) version on OS X?
...
First run /usr/libexec/java_home -V which will output something like the following:
Matching Java Virtual Machines (3):
1.8.0_05, x86_64: "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_05.jdk/Contents/Home
1.6.0_65-b14-462, x86_64: "Java SE...
Is errno thread-safe?
...
@vinit dhatrak There should be # if !defined _LIBC || defined _LIBC_REENTRANT , _LIBC is not defined when compiling normal programs. Anyway, run echo #include <errno.h>' | gcc -E -dM -xc - and look at the difference with and without -pthread. errno is #define er...
Can I use Twitter Bootstrap and jQuery UI at the same time?
...no]
- jquery-ui-1.9.2.custom.min.css
[images]
- ui-bg_diagonals-thick_90_eeeeee_40x40.png
- ui-bg_glass_100_e4f1fb_1x400.png
- ui-bg_glass_50_3baae3_1x400.png
- ui-bg_glass_80_d7ebf9_1x400.png
- ui-bg_highlight-hard_100_f2f5f7_1x100.png
...
Python JSON serialize a Decimal object
...
The problem was that DecimalEncoder()._iterencode(decimal.Decimal('3.9')).next() returned the correct '3.9', but DecimalEncoder()._iterencode(3.9).next() returned a generator object which would only return '3.899...' when you piled on another .next(). Generator f...