大约有 47,000 项符合查询结果（耗时：0.0483秒） [XML]
Adding a column to a data.frame
...according to column 1 ( h_no ) in that way that the first series of h_no 1,2,3,4 is class 1, the second series of h_no (1 to 7) is class 2 etc. such as indicated in the last column.
...
How to convert a string or integer to binary in Ruby?
... number to a string representing the number in the base specified:
9.to_s(2) #=> "1001"
while the reverse is obtained with String#to_i(base):
"1001".to_i(2) #=> 9
share
|
improve this ans...
How can I filter a Django query with a list of values?
...
562
From the Django documentation:
Blog.objects.filter(pk__in=[1, 4, 7])
...
Turn Pandas Multi-Index into column
I have a dataframe with 2 index levels:
3 Answers
3
...
Revert a range of commits in git
...Git are you using?
Reverting multiple commits in only supported in Git1.7.2+: see "Rollback to an old commit using revert multiple times." for more details.
The current git revert man page is only for the current Git version (1.7.4+).
As the OP Alex Spurling reports in the comments:
Upgrading t...
Replace specific characters within strings
...
With a regular expression and the function gsub():
group <- c("12357e", "12575e", "197e18", "e18947")
group
[1] "12357e" "12575e" "197e18" "e18947"
gsub("e", "", group)
[1] "12357" "12575" "19718" "18947"
What gsub does here is to replace each occurrence of "e" with an empty string ""....
Version of SQLite used in Android?
...
482
UPDATE OCT 2016: Here is a link to the updated official docs which includes the main points in t...
Sort rows in data.table in decreasing order on string key `order(-x,v)` gives error on data.table 1.
...o longer necessary.
You can use DT[order(-rank(x), y)].
x y v
1: c 1 7
2: c 3 8
3: c 6 9
4: b 1 1
5: b 3 2
6: b 6 3
7: a 1 4
8: a 3 5
9: a 6 6
share
|
improve this answer
|
...
PHP Foreach Pass by Reference: Last Element Duplicating? (Bug?)
... $item is still a reference to some value which is also being used by $arr[2]. So each foreach call in the second loop, which does not call by reference, replaces that value, and thus $arr[2], with the new value.
So loop 1, the value and $arr[2] become $arr[0], which is 'foo'.
Loop 2, the value and ...
DefaultInlineConstraintResolver Error in WebAPI 2
I'm using Web API 2 and I'm getting the following error when I send a POST to my API method using IIS 7.5 on my local box.
...