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How to join (merge) data frames (inner, outer, left, right)
...s these operations in SQL.
library(sqldf)
## inner join
df3 <- sqldf("SELECT CustomerId, Product, State
FROM df1
JOIN df2 USING(CustomerID)")
## left join (substitute 'right' for right join)
df4 <- sqldf("SELECT CustomerId, Product, State
FROM df1...
How to set breakpoints in inline Javascript in Google Chrome?
...e directory tree underneath it (with the up and down arrow in it), you can select the file you want to debug. You can get out of an error by pressing resume on the right-hand side of the same tab.
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How to set data attributes in HTML elements
...e.
$("#button").on("click", function() {
var field = document.querySelector("#textfield")
switch ($("#method").val()) {
case "setAttribute":
field.setAttribute("data-customval", field.value)
break;
case "dataset":
field.dataset.customval = field.value
...
Installing R with Homebrew
... you don't have XCode Command Line Tools (CLT), run from terminal:
xcode-select --install
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How to create Android Facebook Key Hash?
...of your app on facebook. To get there, go to developers.facebook.com/apps, select your app, go to Edit settings and scroll down. After that, wait a few minutes until the changes take effect.
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Why would you use Expression rather than Func?
...y. Ie. you need database.data.Where(i => i.Id > 0) to be executed as SELECT FROM [data] WHERE [id] > 0. If you just pass in a Func, you've put blinders on your driver and all it can do is SELECT * and then once it's loaded all of that data into memory, iterate through each and filter out ev...
Interactive search/replace regex in Vim?
...info on the options available once substitution with confirmation has been selected. Use:
:h :s
Then scroll to section on confirm options. Screenshot below:
For instance, to substitute this and all remaining matches, use a.
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Summarizing multiple columns with dplyr? [duplicate]
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I mean, the behavior like in select would be great: summarize(df, a:c, d=paste(d, collaspe =',' ) . Just want to put more original columns in for reference
– biocyberman
Aug 8 '15 at 17:28
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Searching if value exists in a list of objects using Linq
...from customer in list
where customer.FirstName == "John"
select customer).Any();
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Facebook database design?
...O_INCREMENT=2 DEFAULT CHARSET=utf8;
Friends of Friends Query:
(
select friend_id
from friends
where user_id = 1
) union (
select distinct ff.friend_id
from
friends f
join friends ff on ff.user_id = f.friend_id
where f.use...