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Accessing the logged-in user in a template
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edited Sep 19 '11 at 12:57
answered Sep 19 '11 at 11:24
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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...
How should I handle “No internet connection” with Retrofit on Android
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answered Mar 23 '14 at 19:22
AlexVAlexV
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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...
Set scroll position
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182
You can use window.scrollTo(), like this:
window.scrollTo(0, 0); // values are x,y-offset
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Are the shift operators () arithmetic or logical in C?
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11 Answers
11
Active
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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...