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Our task is create a table, and read values to the table using a loop. Print the values after the process is complete. - Create a table. - Read the number of values to be read to the table. - Read the values to the table using a loop. - Print the values in the table using another loop. for this we had written code as
local table = {}
for value in ipairs(table) do
io.read()
end
for value in ipairs(table) do
print(value)
end
not sure where we went wrong please help us. Our exception is
Input (stdin)
3
11
22
abc
Your Output (stdout)
~ no output ~
Expected Output
11
22
abc
Correct Code is
local table1 = {}
local x = io.read()
for line in io.lines() do
table.insert(table1, line)
end
for K, value in ipairs(table1) do
print(value)
end
Let's walk through this step-by-step.
Create a table.
Though the syntax is correct, table is a reserved pre-defined global name in Lua, and thus cannot should not be declared a variable name to avoid future issues. Instead, you'll need to want to use a different name. If you're insistent on using the word table, you'll have to distinguish it from the function global table. The easiest way to do this is change it to Table, as Lua is a case-sensitive language. Therefore, your table creation should look something like:
local Table = {}
Read values to the table using a loop.
Though Table is now established as a table, your for loop is only iterating through an empty table. It seems your goal is to iterate through the io.read() instead. But io.read() is probably not what you want here, though you can utilize a repeat loop if you wish to use io.read() via table.insert. However, repeat requires a condition that must be met for it to terminate, such as the length of the table reaching a certain amount (in your example, it would be until (#Table == 4)). Since this is a task you are given, I will not provide an example, but allow you to research this method and use it to your advantage.
Print the values after the process is complete.
You are on the right track with your printing loop. However, it must be noted that iterating through a table always returns two results, an index and a value. In your code, you would only return the index number, so your output would simply return:
1
2
3
4
If you are wanting the actual values, you'll need a placeholder for the index. Oftentimes, the placeholder for an unneeded variable in Lua is the underscore (_). Modify your for loop to account for the index, and you should be set.
Try modifying your code with the suggestions I've given and see if you can figure out how to achieve your end result.
Edited:
Thanks, Piglet, for corrections on the insight! I'd forgotten table itself wasn't a function, and wasn't reserved, but still bad form to use it as a variable name whether local or global. At least, it's how I was taught, but your comment is correct!
I have two related to each other questions. I need some best practices.
First part..
Im searching best place to put data parser from text area. I do not want to insert that data to database, just read from text area after that compare that with some data and do some action (no any data from database). Where would u place that parsers? I should use helper (for now I use helpers just in view), concerns or just model methods?
Second part..
For example, lets input data looks like:
A B H 0 2
C D R 1 3
E F E 4 9
R H T 1 0
I parse that data from text area, split by column, check regex, if there is 5 cols etc. I need to create list of objects, and where could i create that 'helper' class with fields like first_col, sec_col, third_col, that data will be not saved to database..?
I think it's the job of a service object. You will pass the text to your service, it will work with your param and return the result, anywhere in your app.
I am using influxDB and using line protocol to insert large set of data into Data base. Data i am getting is in the form of Key value pair, where key is long string contains Hierarchical data and value is simple integer value.
Sample Key Value data :
/path/units/unit/subunits/subunit[name\='NAME1']/memory/chip/application/filter/allocations
value = 500
/path/units/unit/subunits/subunit[name\='NAME2']/memory/chip/application/filter/allocations
value = 100
(Note Name = 2)
/path/units/unit/subunits/subunit[name\='NAME1']/memory/chip/application/filter/free
value = 700
(Note Instead of allocation it is free at the leaf)
/path/units/unit/subunits/subunit[name\='NAME2']/memory/graphics/application/filter/swap
value = 600
Note Instead of chip, graphics is in path)
/path/units/unit/subunits/subunit[name\='NAME2']/harddisk/data/size
value = 400
Note Different path but till subunit it is same
/path/units/unit/subunits/subunit[name\='NAME2']/harddisk/data/free
value=100
Note Same path but last element is different
Below is the line protocol i am using to insert data.
interface, Key= /path/units/unit/subunits/subunit[name\='NAME2']/harddisk/data/free, valueData= 500
I am Using one measurement namely, Interface. And one tag and one field set. But this DB design is causing issue for querying data.
How can I design database so that i can query like, Get all record for subunit where name = Name1 or get all size data for every hard disk.
Thanks in advance.
The Schema I'd recommend would be the following:
interface,filename=/path/units/unit/subunits/subunit[name\='NAME2']/harddisk/data/free value=500
Where filename is a tag and value is the field.
Given that the cardinality of filename in the thousands this schema should work well.
I have a sample data looks like:
1950,0,1
1950,22,1
1950,-11,1
1949,111,1
1949,78,1
and I used following commands:
A = load 'path/to/the/sample';
B = foreach A generate $0,$1;
which should only generate first 2 columns of the A.
then I used
describe B
to check how it works, it returns: B: {a: bytearray,b: bytearray}, that is correct.
HOWEVER, when I run the command
dump B
why it returns:
(1950,0,1,)
(1950,22,1,)
(1950,-11,1,)
(1949,111,1,)
(1949,78,1,)
as the result??? It's sooooo weird. I'v tried it several time... but still the same result
The reason this happens is because Pig by default tries to separate your data by tabs. So when you pass it a line like
1950,0,1
it thinks it has found just a single field, 1950,0,1. Since you indicated that each line has two fields, the second field is just set to NULL.
So when you GENERATE the two fields you loaded, it prints out the tuple
(1950,0,1,)
If you were to STORE this instead of DUMPing it you would see it more clearly. Pig would store the data separated by tabs (again, the default), and your output file would look like
1950,0,1
1950,22,1
1950,-11,1
1949,111,1
1949,78,1
That's not very enlightening, so look instead what happens if you were to do this:
B = foreach A generate $0, "test";
store B into 'output';
Now the data in output would be
1950,0,1 test
1950,22,1 test
1950,-11,1 test
1949,111,1 test
1949,78,1 test
You can control what Pig uses as the field separator for both LOAD and STORE by using the clause USING PigStorage(','). The argument to PigStorage can be whatever character you like. One other common one is USING PigStorage('\n'), which will load in each line as a whole.
Use PigStorage Clause in your Load statement.
A = load 'path/to/the/sample' using PigStorage(',');
B = foreach A generate $0,$1;
dump B
now you will get the result that what u expect
(1950,0)
(1950,22)
(1950,-11)
(1949,111)
(1949,78)
INFORMIX-SQL 7.3 Perform Screens:
According to documentation, in an "after editadd editupdate of table" control block, its instructions are executed before the row is added or updated to the table, whereas in an "after add update of table" control block, its instructions are executed after the row has been added or updated to the table. Supposedly, this would mean that any instructions which would alter values of field-tags linked to table.columns would not be committed to the table, but field-tags linked to displayonly fields will change?
However, when using "after add update of table", I placed instructions which alter values for field-tags linked to table.columns and their displayed and committed values also changed! I would have thought that an "after add update of table" would only alter displayonly fields.
TABLES
customer
transaction
branch
interest
dates
ATTRIBUTES
[...]
q = transaction.trx_type, INCLUDE=("E","C","V","P","T"), ...;
tb = transaction.trx_int_table,
LOOKUP f1 = ta_days1_f,
t1 = ta_days1_t,
i1 = ta_int1,
[...]
JOINING *interest.int_table, ...;
[...]
INSTRUCTIONS
customer MASTER OF transaction
transaction MASTER OF customer
delimiters ". ";
AFTER QUERY DISPLAY ADD UPDATE OF transaction
if z = "E" then let q = "E"
if z = "C" then let q = "C"
if z = "1" then let q = "E"
[...]
END
Is 'z' a column in the transaction table?
Is the trouble that the value in 'z' is causing a change in the value of 'q' (aka transaction.trx_type), and the modified value is being stored in the database?
Is the value in 'z' part of the transaction table?
Have you verified that the value in the DB is indeed changed - using the Query Language option or a simple (default) form?
It might look as if it is because the instruction is also used AFTER DISPLAY, so when the values are retrieved from the DB, the value displayed in 'q' would be the mapped values corresponding to the value stored in 'z'. You would have to inspect the raw data to hide that mapping.
If this is not the problem, please:
Amend the question to show where 'z' comes from.
Also describe exactly what you do and see.
Confirm that the data in the database, as opposed to on the screen, is amended.
Please can you see whether this table plus form behaves the same for you as it does for me?
Table Transaction
CREATE TABLE TRANSACTION
(
trx_id SERIAL NOT NULL,
trx_type CHAR(1) NOT NULL,
trx_last_type CHAR(1) NOT NULL,
trx_int_table INTEGER NOT NULL
);
Form
DATABASE stores
SCREEN SIZE 24 BY 80
{
trx_id [f000]
trx_type [q]
trx_last_type [z]
trx_int_table [f001 ]
}
END
TABLES
transaction
ATTRIBUTES
f000 = transaction.trx_id;
q = transaction.trx_type, UPSHIFT, AUTONEXT,
INCLUDE=("E","C","V","P","T");
z = transaction.trx_last_type, UPSHIFT, AUTONEXT,
INCLUDE=("E","C","V","P","T","1");
f001 = transaction.trx_int_table;
INSTRUCTIONS
AFTER ADD UPDATE DISPLAY QUERY OF transaction
IF z = "E" THEN LET q = "E"
IF z = "C" THEN LET q = "C"
IF z = "1" THEN LET q = "E"
END
Experiments
[The parenthesized number is automatically generated by IDS/Perform.]
Add a row with data (1), V, E, 23.
Observe that the display is: 1, E, E, 23.
Exit the form.
Observe that the data in the table is: 1, V, E, 23.
Reenter the form and query the data.
Update the data to: (1), T, T, 37.
Observe that the display is: 1, T, T, 37.
Exit the form.
Observe that the data in the table is: 1, T, T, 37.
Reenter the form and query the data.
Update the data to: (1), P, 1, 49
Observe that the display is: 1, E, 1, 49.
Exit the form.
Observe that the data in the table is: 1, P, 1, 49.
Reenter the form and query the data.
Observe that the display is: 1, E, 1, 49.
Choose 'Update', and observe that the display changes to: 1, P, 1, 49.
I did the 'Observe that the data in the table is' steps using:
sqlcmd -d stores -e 'select * from transaction'
This generated lines like these (reflecting different runs):
1|V|E|23
1|P|1|49
That is my SQLCMD program, not Microsoft's upstart of the same name. You can do more or less the same thing with DB-Access, except it is noisier (13 extraneous lines of output) and you would be best off writing the SELECT statement in a file and providing that as an argument:
$ echo "select * from transaction" > check.sql
$ dbaccess stores check
Database selected.
trx_id trx_type trx_last_type trx_int_table
1 P 1 49
1 row(s) retrieved.
Database closed.
$
Conclusions
This is what I observed on Solaris 10 (SPARC) using ISQL 7.50.FC1; it matches what the manual describes, and is also what I suggested in the original part of the answer might be the trouble - what you see on the form is not what is in the database (because of the INSTRUCTIONS section).
Do you see something different? If so, then there could be a bug in ISQL that has been fixed since. Technically, ISQL 7.30 is out of support, I believe. Can you upgrade to a more recent version than that? (I'm not sure whether 7.32 is still supported, but you should really upgrade to 7.50; the current release is 7.50.FC4.)
Transcribing commentary before deleting it:
Up to a point, it is good that you replicate my results. The bad news is that in the bigger form we have different behaviour. I hope that ISQL validates all limits - things like number of columns etc. However, there is a chance that they are not properly validated, given the bug, or maybe there is a separate problem that only shows with the larger form. So, you need to ensure you have a supported version of the product and that the problem reproduces in it. Ideally, you will have a smaller version of the table (or, at least, of the form) that shows the problem, and maybe a still smaller (but not quite as small as my example) version that shows the absence of the problem.
With the test case (table schema and Perform screen that shows the problem) in hand, you can then go to IBM Tech Support with "Look - this works correctly when the form is small; and look, it works incorrectly when the form is large". The bug should then be trackable. You will need to include instructions on how to reproduce the bug similar to those I gave you. And there is no problem with running two forms - one simple and one more complex and displaying the bug - in parallel to show how the data is stored vs displayed. You could describe the steps in terms of 'Form A' and 'Form B', with Form A being Absolutely OK and Form B being Believed to be Buggy. So, add a record with certain values in Form B; show what is displayed in Form B after; show what is stored in the database in Form A after too; show that they are not different when they should be.
Please bear in mind that those who will be fixing the issue have less experience with the product than either you or me - so keep it as simple as possible. Remove as many attributes as you can; leave comments to identify data types etc.