大约有 11,643 项符合查询结果（耗时：0.0164秒） [XML]
Pass a data.frame column name to a function
...1(df, "B")
fun1(df, c("B","A"))
There's no need to use substitute, eval, etc.
You can even pass the desired function as a parameter:
fun1 <- function(x, column, fn) {
fn(x[,column])
}
fun1(df, "B", max)
Alternatively, using [[ also works for selecting a single column at a time:
df <- ...
How to set time delay in javascript
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Place your code inside of the { }
500 = 0.5 seconds
2200 = 2.2 seconds
etc.
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How to implement an android:background that doesn't stretch?
...tton instead of ImageButton (which doesn't allow SetText() , resizing, etc.).
11 Answers
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What is the actual use of Class.forName(“oracle.jdbc.driver.OracleDriver”) while connecting to a dat
...uto-load the driver class. So why do we have to manually do Class.forName("etc.driver") ?
– Pacerier
Aug 28 '14 at 22:52
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How do I choose between Tesseract and OpenCV? [closed]
... image inputs (a single word, line, paragraph, page, limited dictionaries, etc.).
OpenCV, on the other hand, is a computer vision library that includes features that let you perform some feature extraction and data classification. You can create a simple letter segmenter and classifier that performs...
Regular Expression for alphanumeric and underscores
... flavors. \w includes letters with diacritics, letters from other scripts, etc.
– Jan Goyvaerts
Dec 3 '08 at 7:45
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Script entire database SQL-Server
...p level script, certainly not a script to create all tables, procs, udfs, .etc.
7 Answers
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Converting a string to a date in JavaScript
...parts[1]); JavaScript counts months from 0:
// January - 0, February - 1, etc.
var mydate = new Date(parts[0], parts[1] - 1, parts[2]);
console.log(mydate.toDateString());
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What is WebKit and how is it related to CSS?
...ions relating to CSS, jQuery, layouts, cross-browers compatibility issues, etc...
14 Answers
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What should be the values of GOPATH and GOROOT?
...ct trees (e.g. git) with non-go files - e.g. images, scripts, build files, etc?
– Serge Merzliakov
May 17 '19 at 1:44
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