I am doing a small script to get SNMP traps with PySnmp.
I am able to get the oid = value pairs, but the value is too long with a small information in the end. How can I access the octectstring only which comes in the end of the value. Is there a way other than string manipulations? Please comment.
OID =_BindValue(componentType=NamedTypes(NamedType('value', ObjectSyntax------------------------------------------------(DELETED)-----------------(None, OctetString(b'New Alarm'))))
Is it possible to get the output like the following, as is available from another SNMP client:
.iso.org.dod.internet.private.enterprises.xxxx.1.1.2.2.14: CM_DAS Alarm Traps:
Edit - the codes are :
**for oid, val in varBinds:
print('%s = %s' % (oid.prettyPrint(), val.prettyPrint()))
target.write(str(val))**
On screen, it shows short, but on file, the val is so long.
Usage of target.write( str(val[0][1][2])) does not work for all (program stops with error), but the 1st oid(time tick) gets it fine.
How can I get the value from tail as the actual value is found there for all oids.
Thanks.
SNMP transfers information in form of a sequence of OID-value pairs called variable-bindings:
variable_bindings = [[oid1, value1], [oid2, value2], ...]
Once you get the variable-bindings sequence from SNMP PDU, to access value1, for example, you might do:
variable_binding1 = variable_bindings[0]
value1 = variable_binding1[1]
To access the tail part of value1 (assuming it's a string) you could simply subscribe it:
tail_of_value1 = value1[-10:]
I guess in your question you operate on a single variable_binding, not a sequence of them.
If you want pysnmp to translate oid-value pair into a human-friendly representation (of MIB object name, MIB object value), you'd have to pass original OID-value pair to the ObjectType class and run it through MIB resolver as explained in the documentation.
Thanks...
the following codes works like somwwhat I was looking for.
if str(oid)=="1.3.6.1.2.1.1.3.0":
target.write(" = str(val[0][1]['timeticks-value']) = " +str(val[0][1]['timeticks-value'])) # time ticks
else:
target.write("= val[0][0]['string-value']= " + str(val[0][0]['string-value']))
Related
I am having a couple of issues to put this in a functional format.
select from tableName where i=fby[(last;i);([]column_one;column_two)]
This is what I got:
?[tableName;fby;enlist(=;`i;(enlist;last;`i);(+:;(!;enlist`column_one`column_two;(enlist;`column_one;`column_two))));0b;()]
but I get a type error.
Any suggestions?
Consider using the following function, adjust from the buildQuery function given in the whitepaper on Parse Trees. This is a pretty useful tool for quickly developing in q, this version is an improvement on that given in the linked whitepaper, having been extended to handle updates by reference (i.e., update x:3 from `tab)
\c 30 200
tidy:{ssr/[;("\"~~";"~~\"");("";"")] $[","=first x;1_x;x]};
strBrk:{y,(";" sv x),z};
//replace k representation with equivalent q keyword
kreplace:{[x] $[`=qval:.q?x;x;"~~",string[qval],"~~"]};
funcK:{$[0=t:type x;.z.s each x;t<100h;x;kreplace x]};
//replace eg ,`FD`ABC`DEF with "enlist`FD`ABC`DEF"
ereplace:{"~~enlist",(.Q.s1 first x),"~~"};
ereptest:{((0=type x) & (1=count x) & (11=type first x)) | ((11=type x)&(1=count x))};
funcEn:{$[ereptest x;ereplace x;0=type x;.z.s each x;x]};
basic:{tidy .Q.s1 funcK funcEn x};
addbraks:{"(",x,")"};
//where clause needs to be a list of where clauses, so if only one whereclause need to enlist.
stringify:{$[(0=type x) & 1=count x;"enlist ";""],basic x};
//if a dictionary apply to both, keys and values
ab:{$[(0=count x) | -1=type x;.Q.s1 x;99=type x;(addbraks stringify key x),"!",stringify value x;stringify x]};
inner:{[x]
idxs:2 3 4 5 6 inter ainds:til count x;
x:#[x;idxs;'[ab;eval]];
if[6 in idxs;x[6]:ssr/[;("hopen";"hclose");("iasc";"idesc")] x[6]];
//for select statements within select statements
//This line has been adjusted
x[1]:$[-11=type x 1;x 1;$[11h=type x 1;[idxs,:1;"`",string first x 1];[idxs,:1;.z.s x 1]]];
x:#[x;ainds except idxs;string];
x[0],strBrk[1_x;"[";"]"]
};
buildSelect:{[x]
inner parse x
};
We can use this to create the functional query that will work
q)n:1000
q)tab:([]sym:n?`3;col1:n?100.0;col2:n?10.0)
q)buildSelect "select from tab where i=fby[(last;i);([]col1;col2)]"
"?[tab;enlist (=;`i;(fby;(enlist;last;`i);(flip;(lsq;enlist`col1`col2;(enlist;`col1;`col2)))));0b;()]"
So we have the following as the functional form
?[tab;enlist (=;`i;(fby;(enlist;last;`i);(flip;(lsq;enlist`col1`col2;(enlist;`col1;`col2)))));0b;()]
// Applying this
q)?[tab;enlist (=;`i;(fby;(enlist;last;`i);(flip;(lsq;enlist`col1`col2;(enlist;`col1;`col2)))));0b;()]
sym col1 col2
----------------------
bah 18.70281 3.927524
jjb 35.95293 5.170911
ihm 48.09078 5.159796
...
Glad you were able to fix your problem with converting your query to functional form.
Generally it is the case that when you use parse with a fby in your statement, q will convert this function into its k definition. Usually you should just be able to replace this k code with the q function itself (i.e. change (k){stuff} to fby) and this should run properly when turning the query into functional form.
Additionally, if you check out https://code.kx.com/v2/wp/parse-trees/ it goes into more detail about parse trees and functional form. Additionally, it contains a script called buildQuery which will return the functional form of the query of interest as a string which can be quite handy and save time when a functional form is complex.
I actually got it myself ->
?[tableName;((=;`i;(fby;(enlist;last;`i);(+:;(!;enlist`column_one`column_two;(enlist;`column_one;`column_two)))));(in;`venue;enlist`venueone`venuetwo));0b;()]
The issues was a () missing from the statement. Works fine now.
**if someone wants to add a more detailed explanation on how manual parse trees are built and how the generic (k){} function can be replaced with the actual function in q feel free to add your answer and I'll accept and upvote it
Motivation
Modelica does store units of measurement (e.g. SI units and Non-SI units) as an attribute with regard to a variable. Here is an example for a Non-SI-unit:
type Time_months = Real( quantity = "Time", unit = "mo", displayUnit = "months" )
Since for models in economics it will be rather akward to give rates in seconds, I would like to write a rather general unit conversion function that will allow to convert units of time. So ideally a function to convert to another time base should work with three inputs and one output:
input Real timeValue "the value of time to be converted";
input String timeBaseA "the time base for timeValue, e.g. \"mo\" ";
input String timeBaseB "the time base to convert to, e.g. \"yr\" ";
output Real convertedTimeValue "the result of the conversion";
Questions
If we assume that a variable for some time value already has a specific unit attribute (e.g. "mo") it would make sense to use that meta information within a model.
Question 1: How can meta information like unit be accessed within a model?
Ideally something like the following would be great:
String timeBaseA := timeValue.unit;
or
String timeBaseA := getUnit( timeValue ) "some function to read unit information";
Question 2: How can meta information like unit be assigned within a function?
In the example we would of course like to return the output value with the correct unit of time. So ideally we would like to have:
output Real convertedTime( quantity = "Time", unit = strTimeBaseB )
Unfortunately, using an input will give rise to an error as the variability is different: The unit attribute should have constant variability but the input variable has parameter variability. (Using a function - which would be nice - also fails for the same reason.)
Regarding Question 1:
I have never used Wolfram SystemModeler, but the Modelica Language Specification 3.4 says in chapter 4.8 (Predefined Types and Classes):
The attributes of the predefined variable types (Real, Integer, Boolean, String) ... cannot be accessed using dot notation, and are not constrained by equations and algorithm sections.
Regarding Question 2:
I think it is only possible to define the unit of a variable on declaration from a literal or from a final parameter - at least this is what I observed in Dymola.
Alternative - use operator records
You could use operator records for your task. This will allow you to store the time in seconds and convert it to what ever needed when the value comes to use.
Operator records allow you to define several function to create them, compare or add them, convert to String, etc.
See the brief example below, where a operator record Time is defined, which can be created with two different constructor functions from seconds or days and can be converted to Strings with day or seconds
operator record Time
Integer s "Second";
encapsulated operator 'constructor'
import Time;
function from_s
input Integer s "Seconds";
output Time t(s=s);
algorithm
end from_s;
function from_d
input Integer d "Days";
output Time t(s=d*24*3600);
algorithm
end from_d;
end 'constructor';
encapsulated operator 'String' "Convert Time to string"
import Time;
function formated
input Time t;
input String format = "s" annotation(choices(choice="s" "seconds", choice="d" "days"));
output String str;
algorithm
if format == "d" then
str :=String(t.s/24/3600);
else
str :=String(t.s);
end if;
end formated;
end 'String';
encapsulated operator function '==' "Compare time records"
import Time;
input Time t1;
input Time t2;
output Boolean result "= t1 == t2";
algorithm
result := t1.s == t2.s;
end '==';
end Time;
Usage:
import Modelica.Utilities.Streams.print
t1 = Time(d=12) // create record using day constructor
t2 = Time(s=3600*24*2) // create record using second constructor
print(String(t1, format="s")) // prints 1036800
print(String(t1, format="d")) // prints 12
print(String(t2, format="s")) // prints 172800
print(String(t2, format="d")) // prints 2
See Modelica Spec 3.4 Chapter 14 "Overloaded Operators" for details.
Note: This was tested with Dymola 2019, not with Wolfram SystemModeler
In Modelica usually every variable is computed based on SI units. Then you have displayUnits to plot them in a different unit (not affecting the actual computation).
I don't know about SystemModeler, but in Dymola the conversion between the unit (of computation) and the displayUnit (only for plotting) is handled by a pre-defined script (displayUnit.mos). It can be extended by the user to contain custom displayUnits. The code for the display units related to time is shown below. I extended it to have week (w) additionally to the predefined ones.
// Syntax:
// defineUnitConversion(<unit>, <derived unit>, <scale>, <opt. offset>);
// Time
defineUnitConversion("s", "ms", 1000);
defineUnitConversion("s", "min", 1/60);
defineUnitConversion("s", "h", 1/3600);
defineUnitConversion("s", "d", 1/86400);
defineUnitConversion("s", "w", 1/604800);
This can then be selected in plots manually or as the default ´displayUnit´ via Modelica.SIunits.Time t(displayUnit = "w") = ...;
The disadvantage is, that this extension has to be done in a file in the install directory. So it has to be changed again after re-installing the tool or when using a different computer.
If there are numerical reasons to not compute solutions in seconds (e.g. because values would get to big), the solution would be the nominal attribute, which enables a scaling of the variables.
BTW: I think months are not a very good unit of time as they can have 28 to 31 days. That's why I chose weeks in my example.
You could use conversion like is done in the MSL, for example the function Modelica.SIunits.Conversions.to_degC which has the signature:
function to_degC
input Temperature Kelvin "Kelvin value";
output NonSIunits.Temperature_degC Celsius "Celsius value";
end to_degC;
This works, but you need one such function for each unit you want to convert between (which is why most calculations are done using SI-units).
Still trying to understand how to use class. I have now written the following:
`import random
class Grid():
def __init__(self, grid_row, grid_column):
self.__row = grid_row
self.__col = grid_column
self.__board=[]
def make_board(self):
for row in range(self.__row):
self.__board.append([])
for col in range(self.__col):
self.__board[row].append('0')
return self.__board
def change_tile(self):
choices = (0,1,2)
x = random.choice(choices)
y= random.choice(choices)
self.__board[x][y] = str(2)
def __repr__(self):
for row in self.__board:
print( " ".join(row))
g = Grid(3,3)
g.make_board()
g.change_tile()
print(g)
Firstly when I run this I get a grid printed followed by:
TypeError: __str__ returned non-string (type NoneType)
I don't understand why this happens. Second question. If I want to return the self.board, __str only returns the last row (0,0,0).With 'print' all three rows and columns are printed. Is there a way around the issue with 'return'?Is it an issue ( apart from the fact that I want to 'see' what I am doing)?
How would one call Grid(3,3) and get a grid with a randomly placed 2 without having to call each function separately as I have done in my example? Lastly why can I not use the integers 0 or 2, but have to convert everything to a string?. I hope that I have not exceeded the goodwill that exists on this forum by asking so many dumb questions!
The special methods __repr__ and __str__ are required to return a string. If there is no __str__ implementation given, the __repr__ will be used for the string conversion too.
Now in your case, __repr__ prints something instead of returning a string. It actually returns nothing, so None is implicitely returned. You have to change it to return a string. For example like this:
def __repr__(self):
return '\n'.join([' '.join(row) for row in self.__board])
I'm attempting to make a program (for homework) which reads in a file, and then counts the number of times each word is used. For tackling the issue efficiently, I've decided to map all unique words to keys, and then increment the key value each time the word comes up.
function [] = problem2
file_open = fopen('austen.txt');
complete_string = textscan(file_open, '%s');
numel(complete_string{1,1})
unique_words = unique(complete_string{1,1});
length(unique_words);
frequency = zeros(numel(unique_words), 1);
found_frequency = containers.Map(unique_words, frequency);
for i=1:numel(complete_string{1,1})
found_frequency(complete_string{1,1}(i)) = found_frequency(complete_string{1,1}(i))+1;
end
fclose(file_open)
Sadly, this code does not work. When the line comes up to increment, I receive an error stating that "specified key type does not match the type expected for this container", which makes no sense to me - I'm using strings as the keys. Any ideas as to why I'm receiving this error?
The issue was in the use of Cell type - complete_String{1,1}(i) would actually return a Cell rather than a String (per spec, though). Wrapped it in char(*) and it worked fine.
I have a variable called 'int' with alot of data in it. I would like to find a way to programically rename this variable with a user input. So I can query the user indentifcation information about the data, say the response is 'AA1', I want either rename the variable 'int' to 'AA1' or make 'AA1' a variable that is identical to int.
A problem using the input command arises because it allows the user to assign a value to an already created varialbe, instead of actually creating a variable name. Would using the eval function, or a variation of it, help me achieve this? Or is there an easier way?
Thanks!
Just for the record, int is a rather poor variable name choice.
That aside, you can do what you want as follows
say foo is the variable that holds a string that the user input. You can do the following:
% eliminate leading/trailing whitespace
foo = strtrim(foo);
a = regexp('[a-zA-Z][a-zA-Z0-9_]*',foo));
if numel(a) == 0
fprintf('Sorry, %s is not a valid variable name in matlab\n', foo);
elseif a ~= 1
fprintf('Sorry, %s is not a valid variable name in matlab\n', foo);
elseif 2 == exist(foo,'var')
fprintf('Sorry, %s already in use as a variable name.');
else
eval([foo,' = int']);
end
Assuming int (and now foo) is a structure with field named bar, you can read bar as follows:
barVal = eval([foo,'.bar']);
This is all somewhat clunky.
An alternative approach, that is far less clunky is to use an associative array, and let the user store various values of int in the array. The Matlab approach for associative arrays is Maps. That would be my preferred approach to this problem. Here is an example using the same variables as above.
nameValueMap = containers.Map;
nameValueMap(foo) = int;
The above creates the association between the name stored in foo with the data in the variable int.
To get at the data, you just do the following:
intValue = nameValueMap(foo);