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add a string prefix to each value in a string column using Pandas
...['col'].astype(str)
Example:
>>> df = pd.DataFrame({'col':['a',0]})
>>> df
col
0 a
1 0
>>> df['col'] = 'str' + df['col'].astype(str)
>>> df
col
0 stra
1 str0
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How do I select elements of an array given condition?
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answered Jun 13 '10 at 0:50
jfsjfs
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Javascript sort array by two fields
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104
grouperArray.sort(function (a, b) {
var aSize = a.gsize;
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+200
Start By going through the Fingerpaint demo in the sdk sample.
Another Sample:
public class MainActivity extends Activity {
D...
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90
scrollHeight is a regular javascript property so you don't need jQuery.
var test = document.get...
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compileSdkVersion is the API version of Android that you compile against.
buildToolsVersion is...
How to prevent a background process from being stopped after closing SSH client in Linux
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20 Answers
20
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Scaling Node.js
...like to know what the general principles are for scaling node up to, say, 20 queries per second.
1 Answer
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Relative frequencies / proportions with dplyr
...n = n()) %>%
mutate(freq = n / sum(n))
# am gear n freq
# 1 0 3 15 0.7894737
# 2 0 4 4 0.2105263
# 3 1 4 8 0.6153846
# 4 1 5 5 0.3846154
From the dplyr vignette:
When you group by multiple variables, each summary peels off one level of the grouping. That makes ...
MySQL Update Inner Join tables query
I have no idea what the problem is. Using MySQL 5.0 I get a compile error when attempting to run the following MySQL update query:
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