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How to drop columns by name in a data frame
..."z","u"))]
x y
1 1 2
2 2 3
3 3 4
4 4 5
5 5 6
Or, much simpler, use the select argument of the subset function : you can then use the - operator directly on a vector of column names, and you can even omit the quotes around the names !
R> subset(df, select=-c(z,u))
x y
1 1 2
2 2 3
3 3 4
4 4 ...
open read and close a file in 1 line of code
...p", "copyright", "credits" or "license" for more information.
>>> from pathlib import Path
>>> (Path("/etc") / "hostname").read_text()
'dev1.example\n'
On Python 27 install backported pathlib or pathlib2
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Get yesterday's date in bash on Linux, DST-safe
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you can use
date -d "30 days ago" +"%d/%m/%Y"
to get the date from 30 days ago, similarly you can replace 30 with x amount of days
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Direct vs. Delegated - jQuery .on()
...green").on(), binds a click handler directly to the span(s) that match the selector at the moment that code is executed. This means if other spans are added later (or have their class changed to match) they have missed out and will not have a click handler. It also means if you later remove the "gre...
Ineligible Devices section appeared in Xcode 6.x.x
...6 my devices moved to greyed-out section Ineligible Devices and I can't select them as deploy target:
32 Answers
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IntelliJ does not show 'Class' when we right click and select 'New'
... and must have something wrong because when we right click on a directory, select New and then get the context menu, Java based options are not shown. Currently get things like File, some HTML options, XML options.
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postgresql - replace all instances of a string within text field
...g regex replacment. Let's see how easy it is to replace a cat with a dog.
SELECT regexp_replace('Cat bobcat cat cats catfish', 'cat', 'dog');
--> Cat bobdog cat cats catfish
SELECT regexp_replace('Cat bobcat cat cats catfish', 'cat', 'dog', 'i');
--> dog...
Import error: No module name urllib2
...en converting your sources to Python 3.
So you should instead be saying
from urllib.request import urlopen
html = urlopen("http://www.google.com/").read()
print(html)
Your current, now-edited code sample is incorrect because you are saying urllib.urlopen("http://www.google.com/") instead of jus...
Basic http file downloading and saving to disk in python?
...trieve("http://randomsite.com/file.gz", "file.gz")
This downloads a file from a website and names it file.gz. This is one of my favorite solutions, from Downloading a picture via urllib and python.
This example uses the urllib library, and it will directly retrieve the file form a source.
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How can I check whether a option already exist in select by JQuery
How can I check whether a option already exist in select by JQuery?
8 Answers
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