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Sharing Test code in Maven
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190
I recommend using type instead of classifier (see also: classifier). It tells Maven a bit mor...
How to add an auto-incrementing primary key to an existing table, in PostgreSQL?
...mented)
Modern Versions of PostgreSQL
Suppose you have a table named test1, to which you want to add an auto-incrementing, primary-key id (surrogate) column. The following command should be sufficient in recent versions of PostgreSQL:
ALTER TABLE test1 ADD COLUMN id SERIAL PRIMARY KEY;
Older...
Set scroll position
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182
You can use window.scrollTo(), like this:
window.scrollTo(0, 0); // values are x,y-offset
...
When splitting an empty string in Python, why does split() return an empty list while split('\n') re
...espace. For example:
>>> data = '''\
Shasta California 14,200
McKinley Alaska 20,300
Fuji Japan 12,400
'''
>>> for line in data.splitlines():
print line.split()
['Shasta', 'California', '14,200']
['McKinley', 'Alaska', '20,300']
['Fuji...
Group by multiple columns in dplyr, using string vector input
...ike so:
data = data.frame(
asihckhdoydkhxiydfgfTgdsx = sample(LETTERS[1:3], 100, replace=TRUE),
a30mvxigxkghc5cdsvxvyv0ja = sample(LETTERS[1:3], 100, replace=TRUE),
value = rnorm(100)
)
# get the columns we want to average within
columns = names(data)[-3]
library(dplyr)
df1 <- data...
How to upgrade PowerShell version from 2.0 to 3.0
...w.microsoft.com/en-us/download/details.aspx?id=34595. You need Windows 7 SP1 though.
It's worth keeping in mind that PowerShell 3 on Windows 7 does not have all the cmdlets as PowerShell 3 on Windows 8. So you may still encounter cmdlets that are not present on your system.
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How do I compile and run a program in Java on my Mac?
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190
Compiling and running a Java application on Mac OSX, or any major operating system, is very ea...
How to name and retrieve a stash by name in git?
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21 Answers
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