大约有 42,000 项符合查询结果（耗时：0.0621秒） [XML]
Fastest way to determine if an integer's square root is an integer
... follow
|
edited Nov 17 '13 at 23:39
community wiki
...
How to list the tables in a SQLite database file that was opened with ATTACH?
... follow
|
edited Apr 16 '14 at 15:05
Tuan
2,85244 gold badges3232 silver badges5252 bronze badges
...
Difference between Java Enumeration and Iterator
... follow
|
edited Aug 29 at 5:04
SusanW
1,46111 gold badge99 silver badges2121 bronze badges
...
Drop data frame columns by name
...e to keep and refer to them by name :
keeps <- c("y", "a")
DF[keeps]
EDIT :
For those still not acquainted with the drop argument of the indexing function, if you want to keep one column as a data frame, you do:
keeps <- "y"
DF[ , keeps, drop = FALSE]
drop=TRUE (or not mentioning it) wil...
Remove empty array elements
... follow
|
edited Mar 10 at 3:20
answered Sep 6 '10 at 21:10
...
Can I use the range operator with if statement in Swift?
... follow
|
edited Aug 27 '17 at 7:30
Ahmad F
24.5k1313 gold badges6969 silver badges117117 bronze badges
...
How to check that an object is empty in PHP?
... follow
|
edited Apr 5 at 1:24
answered Feb 23 '12 at 11:39
...
How to check if object has any properties in JavaScript?
...s a direct property, and not inherited from the object's prototype chain.
Edit
From the comments: You can put that code in a function, and make it return false as soon as it reaches the part where there is the comment
Performance Test
Test Of Object.Keys vs For..In When testing for any propertie...
Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.10:test
... follow
|
edited Jan 14 at 12:40
zb226
7,01144 gold badges3535 silver badges6262 bronze badges
...
Rails: How does the respond_to block work?
... follow
|
edited Jun 17 '17 at 10:05
Arslan Ali
15.7k77 gold badges4545 silver badges6363 bronze badges
...