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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 '...
Using .gitignore to ignore everything but specific directories
...at I have a bunch of WordPress websites in my git repo, of which I want to selectively commit only the content of my themes folders, while ignoring the rest of the redundant files found in WordPress.
...
How to write a simple database engine [closed]
...h pattern of delimiter is never used in your data itself. i.e. if you have selected <*> for example to separate columns, you should validate the data you are placing in this table not to contain this pattern. you could also use a row header and a column header by specifying size of row and som...
jQuery hasAttr checking to see if there is an attribute on an element [duplicate]
...
What about api.jquery.com/has-attribute-selector
– Aamir Afridi
Jan 30 '13 at 14:19
3
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Converting many 'if else' statements to a cleaner approach [duplicate]
...s not what you need here, this isn't modelling a finite state machine it's selecting a different conversion strategy based on the input type so the strategy pattern is more appropriate.
– Paolo
Jan 3 '13 at 13:55
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pandas: filter rows of DataFrame with operator chaining
...
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 ...
Rails: How to change the title of a page?
...In rails 3 content_for is smart enough to work correctly with caching (see selected answer).
– opsb
Nov 15 '11 at 10:41
4
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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 ...
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...
Real-world examples of recursion [closed]
...( because you want to stop this fast ).
After processing a given person, select the person from the front of the queue and apply immunization if needed. Get all their contacts previously unvisited, and then test to see if they're infected.
Repeat until the queue of infected people becomes 0, and...