大约有 47,000 项符合查询结果（耗时：0.0636秒） [XML]
How to extract the first two characters of a string in shell scripting?
...
Probably the most efficient method, if you're using the bash shell (and you appear to be, based on your comments), is to use the sub-string variant of parameter expansion:
pax> long="USCAGol.blah.blah.blah"
pax> short="${long:0:2}" ; echo "${short}"
US
This will set short to be the f...
Remove duplicated rows using dplyr
...mple(0:1, 10, replace = T),
z = 1:10
)
One approach would be to group, and then only keep the first row:
df %>% group_by(x, y) %>% filter(row_number(z) == 1)
## Source: local data frame [3 x 3]
## Groups: x, y
##
## x y z
## 1 0 1 1
## 2 1 0 2
## 3 1 1 4
(In dplyr 0.2 you won't need...
How to render a DateTime in a specific format in ASP.NET MVC 3?
... iterating an IEnumerable<T>. Creating a template is simple enough, and can provide a lot of flexibility too. Create a folder in your views folder for the current controller (or shared views folder) called DisplayTemplates. Inside that folder, add a partial view with the model type you want...
Linq: GroupBy, Sum and Count
...
I don't understand where the first "result with sample data" is coming from, but the problem in the console app is that you're using SelectMany to look at each item in each group.
I think you just want:
List<ResultLine> result = Lin...
PyCharm shows unresolved references error for valid code
I am using PyCharm to work on a project. The project is opened and configured with an interpreter, and can run successfully. The remote interpreter paths are mapped properly. This seems to be the correct configuration, but PyCharm is highlighting my valid code with "unresolved reference" errors, ...
How to iterate over a JavaScript object?
...{
console.log(key, yourobject[key]);
}
With ES6, if you need both keys and values simultaneously, do
for (let [key, value] of Object.entries(yourobject)) {
console.log(key, value);
}
To avoid logging inherited properties, check with hasOwnProperty :
for (let key in yourobject) {
if (y...
Using curl POST with variables defined in bash script functions
...script. This saves you from all sort of headaches concerning shell quoting and makes it easier to read an maintain the script than feeding the post data on curl's invocation line as in your attempt:
generate_post_data()
{
cat <<EOF
{
"account": {
"email": "$email",
"screenName": "...
How do you make an array of structs in C?
... a question about the placement between the declaration of the struct type and then actually making an instance of it - I have a different struct, one that I defined the contents of below where I first make an instance of it (just one this time, not an array), so why didn't this make the massive ser...
Position of least significant bit that is set
...hed. My favourite solution for your problem (from that site) is «multiply and lookup»:
unsigned int v; // find the number of trailing zeros in 32-bit v
int r; // result goes here
static const int MultiplyDeBruijnBitPosition[32] =
{
0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17...
Differences between Java 8 Date Time API (java.time) and Joda-Time
I know there are questions relating to java.util.Date and Joda-Time. But after some digging, I couldn't find a thread about the differences between the java.time API (new in Java 8 , defined by JSR 310 ) and Joda-Time .
...