Is there anyway to make .find not remove zeropadding on the values it pulls back from the database?
ie. I have zipcodes in a database and some of them are shorter than 5 characters. I am zeropadding thme back to 5 characters in the database, so I end up with "00210" for example. However, this value just becomes "210" in my array.
I know I can use "%05d" % value to zeropad it when it's going back into the views... but I'd rather not have to zeropad it on the way out like that.
A Fixnum (the Ruby type you're dealing with) only cares about value. my_var = 00000001 in ruby sets my_var to 1, and outputting it as a string results in "1". If you want to format it differently, you'll have to rely on string functionality.
Related
According to the documentation, pg_attribute.attgenerated is typed as char and has a value of "a zero byte" if the column is not generated, and there is at least one other possible value, with potentially more in the future.
I want to query for all non-generated columns. Since I would prefer to not be tripped up by additions in future versions, the query predicate needs to be WHERE attgenerated = ZERO BYTE rather than an inequality, but I have no idea how to represent that value correctly in SQL.
What's the correct way to write this? In most programming languages you'd say '\0', and you can use escape sequences by prepending an e to the string literal, but if I say e'\0' it errors out with "invalid byte sequence for encoding "UTF8": 0x00". So I'm not quite sure what the right way to do this is.
It's simply an empty string:
WHERE attgenerated = ''
I'm new to SAS and I'm trying to understand a code:
if MAP_ID="+" then output WORK.0201_template;
else
do;
SHEET_ID=MAP_ID;
output WORK.0201_template_f;
end;
What does it mean the MAP_ID="+"? Does it mean that it search on the table for the values where MAP_ID=+, or does it have another menaing?
Thanks
The MAP_ID="+" is a boolean expression that compares the value the variable MAP_ID to the character string literal "+". It will be true when they are the same and false otherwise.
I suspect that the main purpose of this code is to split the data into two different output datasets based on the value of MAP_ID.
It also is changing the value of SHEET_ID. That type of code also looks like something that is designed to carry forward the value of MAP_ID in a retained field SHEET_ID. If I am right then the meaning of the value of + is to keep the same sheet_id. But we would need to seem more of the code and the data to really tell.
In my Room model, I have an attribute named available_days, which is being stored as an array.
For example:
Room.first.available_days
=> ["wed", "thurs", "fri"]
What is the best way to find all Rooms where the size of the array is equal to 3?
I've tried something like
Room.where('LENGTH(available_days) = ?', 3)
with no success.
Update: the data type for available_days is a string, but in order to store an array, I am serializing the attribute from my model:
app/models/room.rb
serialize :available_days
Can't think of a purely sql way of doing it for sqlite since available_days is a string.
But here's one way of doing it without loading all records at once.
rooms = []
Room.in_batches(of: 10).each_record do |r|
rooms << r if r.available_days.length == 3
end
p rooms
If you're using postgres you can parse the serialized string to an array type, then query on the length of the array. I expect other databases may have similar approaches. How to do this depends on how the text is being serialized, but by default for Rails 4 should be YAML, so I expect you data is encoded like this:
---
- first
- second
The following SQL will remove the leading ---\n- as well as the final newline, then split the remaining string on - into an array. It's not strictly necessary to cleanup the extra characters to find the length, but if you want to do other operations you may find it useful to have a cleaned up array (no leading characters or trailing newline). This will only work for simple YAML arrays and simple strings.
Room.where("ARRAY_LENGTH(STRING_TO_ARRAY(RTRIM(REPLACE(available_days,'---\n- ',''),'\n'), '\n- '), 1) = ?", 3)
As you can see, this approach is rather complex. If possible you may want to add a new structured column (array or jsonb) and migrate the serialized string into the a typed column to make this easier and more performant. Rails supports jsonb serialization for postgres.
I'm pretty new to progress and I want to ask a question.
How do I change variable (string) length in runtime?
ex.
define variable cname as char.
define variable clen as int.
cname= "".
DO cnts = 1 TO 5.
IF prc[cnts] <> "" THEN DO:
clen = clen + LENGTH(prc[cnts]).
cname = cname + prc[cnts].
END.
END.
Put cname format '???' at 1. /here change variable length/
Thanks for the reply
If the PUT statement is what you want to change, then
PUT UNFORMATTED cname.
will write the entire string out without having to worry about the length of the FORMAT phrase.
If you need something formatted, then
PUT UNFORMATTED STRING(cname, fill("X", clen)).
will do what you want. Look up the "STRING()" function in the ABL Ref docs.
In Progress 4GL all data is variable length.
This is one of the big differences between Progress and lots of other development environments. (And in my opinion a big advantage.)
Each datatype has a default format, which you can override, but that is only for display purposes.
Display format has no bearing on storage.
You can declare a field with a display format of 3 characters:
define variable x as character no-undo format "x(3)".
And then stuff 60 characters into the field. Progress will not complain.
x = "123456789012345678901234567890123456789012345678901234567890".
It is extremely common for 4gl application code to over-stuff variables and fields.
(If you then use SQL-92 to access the data you will hear much whining and gnashing of teeth from your SQL client. This is easily fixable with the "dbtool" utility.)
You change the display format when you define something:
define variable x as character no-undo format "x(30)".
or when you use it:
put x format "x(15)".
or
display x format "x(43)".
(And in many other ways -- these are just a couple of easy examples.)
Regardless of the display format the length() function will report the actual length of the data.
I need to store an alphanumeric string in an integer column on one of my models.
I have tried:
#result.each do |i|
hex_id = []
i["id"].split(//).each{|c| hex_id.push(c.hex)}
hex_id = hex_id.join
...
Model.create(:origin_id => hex_id)
...
end
When I run this in the console using puts hex_id in place of the create line, it returns the correct values, however the above code results in the origin_id being set to "2147483647" for every instance. An example string input is "t6gnk3pp86gg4sboh5oin5vr40" so that doesn't make any sense to me.
Can anyone tell me what is going wrong here or suggest a better way to store a string like the aforementioned example as a unique integer?
Thanks.
Answering by request form OP
It seems that the hex_id.join operation does not concatenate strings in this case but instead sums or performs binary complement of the hex values. The issue could also be that hex_id is an array of hex-es rather than a string, or char array. Nevertheless, what seems to happen is reaching the maximum positive value for the integer type 2147483647. Still, I was unable to find any documented effects on array.join applied on a hex array, it appears it is not concatenation of the elements.
On the other hand, the desired result 060003008600401100500050040 is too large to be recorded as an integer either. A better approach would be to keep it as a string, or use different algorithm for producing a number form the original string. Perhaps aggregating the hex values by an arithmetic operation will do better than join ?