大约有 42,000 项符合查询结果（耗时：0.0406秒） [XML]
Impossible to Install PG gem on my mac with Mavericks
...
253
If you want to avoid using MacPorts, you can download the Postgres App and place it into the App...
How to remove an element from a list by index
...y the index of the element you want to delete:
>>> a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> del a[-1]
>>> a
[0, 1, 2, 3, 4, 5, 6, 7, 8]
Also supports slices:
>>> del a[2:4]
>>> a
[0, 1, 4, 5, 6, 7, 8, 9]
Here is the section from the tutorial.
...
Get decimal portion of a number with JavaScript
I have float numbers like 3.2 and 1.6 .
22 Answers
22
...
C# short/long/int literal format?
...
315
var d = 1.0d; // double
var d0 = 1.0; // double
var d1 = 1e+3; // double
var d2 = 1e-3; ...
Count number of records returned by group by
...
13 Answers
13
Active
...
How to implement a queue with three stacks?
...SUMMARY
O(1) algorithm is known for 6 stacks
O(1) algorithm is known for 3 stacks, but using lazy evaluation which in practice corresponds to having extra internal data structures, so it does not constitute a solution
People near Sedgewick have confirmed they are not aware of a 3-stack solution wi...
Rails: Check output of path helper from console
... a Rails console, you can call app.post_path. This will work in Rails ~= 2.3 and >= 3.1.0.
share
|
improve this answer
|
follow
|
...
Some built-in to pad a list in python
...
answered Aug 9 '10 at 9:43
John La RooyJohn La Rooy
249k4646 gold badges326326 silver badges469469 bronze badges
...
How do I replace NA values with zeros in an R dataframe?
...
See my comment in @gsk3 answer. A simple example:
> m <- matrix(sample(c(NA, 1:10), 100, replace = TRUE), 10)
> d <- as.data.frame(m)
V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
1 4 3 NA 3 7 6 6 10 6 5
2 9 8 9 5 10 NA 2 1 7 ...
Two-dimensional array in Swift
...ray of arrays of Ints set to 0. Arrays size is 10x5
var arr = Array(count: 3, repeatedValue: Array(count: 2, repeatedValue: 0))
// ...and for Swift 3+:
var arr = Array(repeating: Array(repeating: 0, count: 2), count: 3)
Change element at position
arr[0][1] = 18
OR
let myVar = 18
arr[0][1] = m...