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MySQL how to join tables on two fields
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SELECT *
FROM t1
JOIN t2 USING (id, date)
perhaps you'll need to use INNEER JOIN or
where t2.id is not null
if you want results only matching both conditions
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Bash command to sum a column of numbers [duplicate]
... With bc -l you can even add up float numbers. With cut you can select columns from the input: cat input.txt | cut -d ' ' -f 8 | paste -sd+ | bc -l will add all float numbers in column 8 of the input (space being the field separator).
– Arne
Sep 24 '...
pull out p-values and r-squared from a linear regression
... need. The beta, se, t and p vectors are stored in it. Get the p-values by selecting the 4th column of the coefficients matrix (stored in the summary object):
summary(fit)$coefficients[,4]
summary(fit)$r.squared
Try str(summary(fit)) to see all the info that this object contains.
Edit: I had ...
jQuery hasAttr checking to see if there is an attribute on an element [duplicate]
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What about api.jquery.com/has-attribute-selector
– Aamir Afridi
Jan 30 '13 at 14:19
3
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pandas: filter rows of DataFrame with operator chaining
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Since version 0.18.1 the .loc method accepts a callable for selection. Together with lambda functions you can create very flexible chainable filters:
import numpy as np
import pandas as pd
df = pd.DataFrame(np.random.randint(0,100,size=(100, 4)), columns=list('ABCD'))
df.loc[lambda ...
Convert data.frame columns from factors to characters
... can create a logical vector of which columns are factors, and use that to selectively apply factor
f <- sapply(bobf, class) == "factor"
bobc[,f] <- lapply(bobc[,f], factor)
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What are some methods to debug Javascript inside of a UIWebView?
...e sure "Show Develop Menu in Menubar" is on.
From the Menu-bar (of Safari) select Develop -> iPhone Simulator -> [your webview page].
That's it !
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ERROR 1452: Cannot add or update a child row: a foreign key constraint fails
... table. Following query would be helpful to fetch those non-matching rows:
SELECT child_table.*
FROM child_table
LEFT JOIN parent_table
ON parent_table.referenced_column = child_table.referencing_column
WHERE parent_table.referenced_column IS NULL
Now, you can generally do one (or more) of th...
Start a git commit message with a hashmark (#)
...y that behavior is wanted.
git 2.0.x/2.1 (Q3 2014) will add an automatic selection for core.commentChar:
See commit 84c9dc2
When core.commentChar is "auto", the comment char starts with '#' as in default but if it's already in the prepared message, find another char in a small subset. This should...
How can I disable a button in a jQuery dialog from a function?
...line that will be of use (under the "buttons" section.
var buttons = $('.selector').dialog('option', 'buttons');
You'll need to get the buttons collection from the dialog, loop through that to find which one you need, and then set the disabled attribute as I showed above.
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