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Elegant setup of Python logging in Django
...ust depends on your requirements. The key thing is that I usually add the handlers I want to the root logger, using levels and sometimes logging.Filters to get the events I want to the appropriate files, console, syslogs etc. You can of course add handlers to any other loggers too, but there isn't c...
Which iomanip manipulators are 'sticky'?
...xcept setw which seems to be reset after use.
By Charles:
Exactly! and the only reason that setw appears to behave differently is because there are requirements on formatted output operations to explicitly .width(0) the output stream.
The following is the discussion that lead to the above ...
difference between primary key and unique key
...ey, unique key, etc are collectively called as Candidate Key.
However, DBA selected a key from candidate key for searching records is called Primary key.
Difference between Primary Key and Unique key
1. Behavior: Primary Key is used to identify a row (record) in a table, whereas Unique-key is to...
Loop through files in a folder using VBA?
...2 Then
FileExtStr = ".xls": FileFormatNum = -4143
Else
Select Case xWb.FileFormat
Case 51:
FileExtStr = ".xlsx": FileFormatNum = 51
Case 52:
If Application.ActiveWorkbook.HasVBProject Then
FileExtStr = "....
How do I use IValidatableObject?
...ustom model binder):
var resultsGroupedByMembers = validationResults
.SelectMany(vr => vr.MemberNames
.Select(mn => new { MemberName = mn ?? "",
Error = vr.ErrorMessage }))
.GroupBy(x => x.MemberName);
foreach (v...
HQL ERROR: Path expected for join
...
select u from UserGroup ug inner join ug.user u
where ug.group_id = :groupId
order by u.lastname
As a named query:
@NamedQuery(
name = "User.findByGroupId",
query =
"SELECT u FROM UserGroup ug " +
"INNER JOIN...
How to query as GROUP BY in django?
...nnotate(dcount=Count('designation'))
This results in a query similar to
SELECT designation, COUNT(designation) AS dcount
FROM members GROUP BY designation
and the output would be of the form
[{'designation': 'Salesman', 'dcount': 2},
{'designation': 'Manager', 'dcount': 2}]
...
Parsing huge logfiles in Node.js - read in line-by-line
...
'line-by-line' is more memory efficient than the selected answer. For 1 million lines in a csv the selected answer had my node process in the low 800s of megabytes. Using 'line-by-line' it was consistently in the low 700s. This module also keeps the code clean and easy to r...
What does a space mean in a CSS selector? i.e. What is the difference between .classA.classB and .cl
What is the difference between these two selectors?
3 Answers
3
...
Aggregate / summarize multiple variables per group (e.g. sum, mean)
...-date), sum)
# summarising a specific set of non-grouping variables using select_helpers
# see ?select_helpers for more options
df2 <- df1 %>% group_by(year, month) %>% summarise_at(vars(starts_with('x')), sum)
df2 <- df1 %>% group_by(year, month) %>% summarise_at(vars(matches('.*...