I have got a string that represents a query. It begins with a function, and the argument is a dictionary.
"runQuery `syms`columns`fastQuery`exchange!((`AAPL`MSFT`GOOG`AMD);(`sym`price`date);1b;`nasdaq)"
How can I extract the dictionary from the string, and save it in kdb as a dictionary type?
parse the string, to get the parse tree, and then take the param (the dict):
q)eval last parse "runQuery `syms`columns`fastQuery`exchange!((`AAPL`MSFT`GOOG`AMD);(`sym`price`date);1b;`nasdaq)"
syms | `AAPL`MSFT`GOOG`AMD
columns | `sym`price`date
fastQuery| 1b
exchange | `nasdaq
For this example value can have the desired effect:
q)myDict:value {(first where x=" ")_x}"runQuery `syms`columns`fastQuery`exchange!((`AAPL`MSFT`GOOG`AMD);(`sym`price`date);1b;`nasdaq)"
q)myDict
syms | `AAPL`MSFT`GOOG`AMD
columns | `sym`price`date
fastQuery| 1b
exchange | `nasdaq
If you have free rein to (re)define the function then you could just do:
q)runQuery:{x}
q)value"runQuery `syms`columns`fastQuery`exchange!((`AAPL`MSFT`GOOG`AMD);(`sym`price`date);1b;`nasdaq)"
syms | `AAPL`MSFT`GOOG`AMD
columns | `sym`price`date
fastQuery| 1b
exchange | `nasdaq
This could be quite useful if you're replaying a tickerplant-style log using -11!
Related
In Excel, I have a list with multiple rows of the same ID (column A), each with various dates recorded (Column B). I need to extract one row for each ID that contains the newest date. See below for example:
|Column A | Column B|
|(ID) | (Date) |
|-----------|-----------|
|00001 | 01/01/2022|
|00001 | 02/01/2022|
|00001 | 03/01/2022| <-- I Need this one
|00002 | 01/02/2022|
|00002 | 02/02/2022|
|00002 | 03/02/2022| <-- I Need this one
|00003 | 01/03/2022|
|00003 | 02/03/2022|
|00003 | 03/03/2022| <-- I Need this one
|00004 | 01/04/2022|
|00004 | 02/04/2022|
|00004 | 03/04/2022| <-- I Need this one
|00005 | 01/05/2022|
|00005 | 02/05/2022|
|00005 | 03/05/2022| <-- I Need this one
I need to extract the above rows, where the row with the newest date is extracted for each unique ID. It needs to look like this:
|Column A | Column B |
|(ID) | (Date) |
|----------|--------------|
|00001 | 03/01/2022 |
|00002 | 03/02/2022 |
|00003 |03/03/2022 |
|00004 | 03/04/2022 |
|00005 | 03/05/2022 |
I'm totally stumped and I can't seem to find the right answer (probably because of how I'm wording the question!)
Thank you!
Google searches for the answer - no joy. I don't know where to start in excel with this function, I thought perhaps DISTINCT or similar...
Assuming you have Office 365 compatible version of Excel, you could do something like this:
(screenshot/here refers):
=INDEX(SORTBY(A2:B11,B2#,-1),SEQUENCE(1,1,1,1),SEQUENCE(1,2,1,1))
This formula is superfluous albeit convenient - you don't really require the first sequence (there's only one row being returned). However, as you can see in the screenshot, using the self-same formula, this time with a leading 2 in the first argument of that sequence returns the top two (descending order) dates, and so forth.
FOR THOSE w/ Office 365 you could do something like this....
=LARGE(B2#+(ROW(B2#)-ROW(B2))/1000,1)
i.e. adding a "little bit" to the dates that we can subtract later and use as a unique reference (row number, original unsorted list)
As mentioned, reverse engineer, throw into an index, and voila!
=INDEX(A2:A11,ROUND((H2-ROUND(H2,0))*1000,6))
caveats:
the round(<>,6) is purely to eliminate Excel's irritating lack of precision issue.
can work if you're looking up text strings (i.e. attempting to sort alphabetically) EXCEPT large doesn't work with string (no prob, just use unicode - but good luck with expanding out the string etc. ☺ with mid(<>,row(a1:offset(a1,len(<>)-1)..,1)..
I am following documentation and thanks to | line_format and regexReplaceAll I was able to fetch some substring from a line.
Let's say now I have those columns:
line
123
7
123
54
14
Having that I want to perform some transform operation, ex sum, or transform operation with grouping by and taking total.
It is not working as I am suspecting those values are not being numbers, but only strings.
Is it possible to convert it to numbers?
I was trying using unwrap but it didn't worked:
sum_over_time(
{service="some"}
|="text expression"
| json
| line_format `{{ regexReplaceAll "text expression to remove from (\\d+)" .label_id "${1}" | trim }}`
| unwrap label_id [1m]
)
it ends up with
pipeline error: 'SampleExtractionErr' for series:
when I am filtering out errors, there is no results.
I am trying to extract the list of column values from a dataframe into a list
+------+----------+------------+
|sno_id|updt_dt |process_flag|
+------+----------+------------+
| 123 |01-01-2020| Y |
+------+----------+------------+
| 234 |01-01-2020| Y |
+------+----------+------------+
| 512 |01-01-2020| Y |
+------+----------+------------+
| 111 |01-01-2020| Y |
+------+----------+------------+
Output should be the list of sno_id ['123','234','512','111']
Then I need to iterate the list to run some logic on each on the list values. I am currently using HiveWarehouseSession to fetch data from hive table into Dataframe by using hive.executeQuery(query)
it is pretty easy as you can first collect the df with will return list of Row type then
row_list = df.select('sno_id').collect()
then you can iterate on row type to convert column into list
sno_id_array = [ row.sno_id for row in row_list]
sno_id_array
['123','234','512','111']
Using Flat map and more optimized solution
sno_id_array = df.select("sno_id ").rdd.flatMap(lambda x: x).collect()
You could use toLocalIterator() to create a generator over the column.
Since you wanted to loop over the results afterwards, this may be more efficient in your case.
Using a generator you don't create and store the list first, but when iterating over the columns you apply your logic immediately:
sno_ids = df.select('sno_id').toLocalIterator()
for row in sno_ids:
sno_id = row.sno_id
# continue with your logic
...
Alternative one-liner using a generator expression:
sno_ids = (row.sno_id for row in df.select('sno_id').toLocalIterator())
for sno_id in sno_ids:
...
Given a table that has a column of time ranges e.g.:
| <2015-10-02>--<2015-10-24> |
| <2015-10-05>--<2015-10-20> |
....
how can I create a column showing the results of org-evalute-time-range?
If I attempt something like:
#+TBLFM: $2='(org-evaluate-time-range $1)
the 2nd column is populated with
Time difference inserted
in every row.
It would also be nice to generate the same result from two different columns with, say, start date and end date instead of creating one column of time ranges out of those two.
If you have your date range split into 2 columns, a simple subtraction works and returns number of days:
| <2015-10-05> | <2015-10-20> | 15 |
| <2013-10-02 08:30> | <2015-10-24> | 751.64583 |
#+TBLFM: $3=$2-$1
Using org-evaluate-time-range is also possible, and you get a nice formatted output:
| <2015-10-02>--<2015-10-24> | 22 days |
| <2015-10-05>--<2015-10-20> | 15 days |
| <2015-10-22 Thu 21:08>--<2015-08-01> | 82 days 21 hours 8 minutes |
#+TBLFM: $2='(org-evaluate-time-range)
Note that the only optional argument that org-evaluate-time-range accepts is a flag to indicate insertion of the result in the current buffer, which you don't want.
Now, how does this function (without arguments) get the correct time range when evaluated is a complete mystery to me; pure magic(!)
I'm currently attempting to modify an existing API that interacts with a postgres database. Long story short, it's essentially stores descriptors/metadata to determine where an actual 'asset' (typically this is a file of some sort) is storing on the server's hard disk.
Currently, its possible to 'tag' these 'assets' with any number of undefined key-value pairs (i.e. uploadedBy, addedOn, assetType, etc.) These tags are stored in a separate table with a structure similar to the following:
+---------------+----------------+-------------+
|assetid (text) | tagid(integer) | value(text) |
|---------------+----------------+-------------|
|someStringValue| 1234 | someValue |
|---------------+----------------+-------------|
|aDiffStringKey | 1235 | a username |
|---------------+----------------+-------------|
|aDiffStrKey | 1236 | Nov 5, 1605 |
+---------------+----------------+-------------+
assetid and tagid are foreign keys from other tables. Think of the assetid representing a file and the tagid/value pair is a map of descriptors.
Right now, the API (which is in Java) creates all these key-value pairs as a Map object. This includes things like timestamps/dates. What we'd like to do is to somehow be able to store different types of data for the value in the key-value pair. Or at least, storing it differently within the database, so that if we needed to, we could run queries checking date-ranges and the like on these tags. However, if they're stored as text items in the db, then we'd have to a.) Know that this is actually a date/time/timestamp item, and b.) convert into something that we could actually run such a query on.
There is only 1 idea I could think of thus far, without complete changing changing the layout of the db too much.
It is to expand the assettag table (shown above) to have additional columns for various types (numeric, text, timestamp), allow them to be null, and then on insert, checking the corresponding 'key' to figure out what type of data it really is. However, I can see a lot of problems with that sort of implementation.
Can any PostgreSQL-Ninjas out there offer a suggestion on how to approach this problem? I'm only recently getting thrown back into the deep-end of database interactions, so I admit I'm a bit rusty.
You've basically got two choices:
Option 1: A sparse table
Have one column for each data type, but only use the column that matches that data type you want to store. Of course this leads to most columns being null - a waste of space, but the purists like it because of the strong typing. It's a bit clunky having to check each column for null to figure out which datatype applies. Also, too bad if you actually want to store a null - then you must chose a specific value that "means null" - more clunkiness.
Option 2: Two columns - one for content, one for type
Everything can be expressed as text, so have a text column for the value, and another column (int or text) for the type, so your app code can restore the correct value in the correct type object. Good things are you don't have lots of nulls, but importantly you can easily extend the types to something beyond SQL data types to application classes by storing their value as json and their type as the class name.
I have used option 2 several times in my career and it was always very successful.
Another option, depending on what your doing, could be to just have one value column but store some json around the value...
This could look something like:
{
"type": "datetime",
"value": "2019-05-31 13:51:36"
}
That could even go a step further, using a Json or XML column.
I'm not in any way PostgreSQL ninja, but I think that instead of two columns (one for name and one for type) you could look at hstore data type:
data type for storing sets of key/value pairs within a single
PostgreSQL value. This can be useful in various scenarios, such as
rows with many attributes that are rarely examined, or semi-structured
data. Keys and values are simply text strings.
Of course, you have to check how date/timestamps converting into and from this type and see if it good for you.
You can use 2 different technics:
if you have floating type for every tagid
Define table and ID for every tagid-assetid combination and actual data tables:
maintable:
+---------------+----------------+-----------------+---------------+
|assetid (text) | tagid(integer) | tablename(text) | table_id(int) |
|---------------+----------------+-----------------+---------------|
|someStringValue| 1234 | tablebool | 123 |
|---------------+----------------+-----------------+---------------|
|aDiffStringKey | 1235 | tablefloat | 123 |
|---------------+----------------+-----------------+---------------|
|aDiffStrKey | 1236 | tablestring | 123 |
+---------------+----------------+-----------------+---------------+
tablebool
+-------------+-------------+
| id(integer) | value(bool) |
|-------------+-------------|
| 123 | False |
+-------------+-------------+
tablefloat
+-------------+--------------+
| id(integer) | value(float) |
|-------------+--------------|
| 123 | 12.345 |
+-------------+--------------+
tablestring
+-------------+---------------+
| id(integer) | value(string) |
|-------------+---------------|
| 123 | 'text' |
+-------------+---------------+
In case if every tagid has fixed type
create tagid description table
tag descriptors
+---------------+----------------+-----------------+
|assetid (text) | tagid(integer) | tablename(text) |
|---------------+----------------+-----------------|
|someStringValue| 1234 | tablebool |
|---------------+----------------+-----------------|
|aDiffStringKey | 1235 | tablefloat |
|---------------+----------------+-----------------|
|aDiffStrKey | 1236 | tablestring |
+---------------+----------------+-----------------+
and correspodnding data tables
tablebool
+-------------+----------------+-------------+
| id(integer) | tagid(integer) | value(bool) |
|-------------+----------------+-------------|
| 123 | 1234 | False |
+-------------+----------------+-------------+
tablefloat
+-------------+----------------+--------------+
| id(integer) | tagid(integer) | value(float) |
|-------------+----------------+--------------|
| 123 | 1235 | 12.345 |
+-------------+----------------+--------------+
tablestring
+-------------+----------------+---------------+
| id(integer) | tagid(integer) | value(string) |
|-------------+----------------+---------------|
| 123 | 1236 | 'text' |
+-------------+----------------+---------------+
All this is just for general idea. You should adapt it for your needs.