I'm trying to run the following th:if:
th:if="${camelContext.getRouteStatus( route.id )} &eq; 'Hey'
but I get this error:
org.thymeleaf.exceptions.TemplateProcessingException: Could not parse as expression: "${camelContext.getRouteStatus( route.id )} &neq; 'Hey' " (camel:92)
However, if I try
th:if="${camelContext.getRouteStatus( route.id )} > 41 "
I get a different error, but now indicating that it's able to parse the expression, its just that it cannot compare Strings and numbers:
Cannot execute GREATER THAN from Expression "${camelContext.getRouteStatus( route.id )} > 41". Left is "Started", right is "41" (camel:92)
That's fine, I just wanted to check if I was writing the syntax correctly, and I don't want to compare numbers anyways, I want to compare the RouteStatus string.
Anyways, maybe someone can help me with this problem? Basically I want to do a if-else on the contents of a string, but I can't get this to work..
Cheers
Have you tried this:
th:if="${camelContext.getRouteStatus( route.id )} == 'Hey'"
Maybe it will work like this?
The example on the thymeleaf shows something similar:
Values in expressions can be compared with the >, <, >= and <= symbols, as usual, and also the == and != operators can be used to check equality (or the lack of it). Note that XML establishes that the < and > symbols should not be used in attribute values, and so they should be substituted by < and >.
th:if="${prodStat.count} gt; 1"
th:text="'Execution mode is ' + ( (${execMode} == 'dev')? 'Development' : 'Production')"
Even though textual aliases exist for some of these operators: gt (>), lt (<), ge (>=), le (<=), not (!). Also eq (==), neq/ne (!=), it is sometimes still better to stick with the old fashion operators.
It seems that your expression is malformed, but maybe this a copy paste issue.
Could you try: th:if="${camelContext.getRouteStatus( route.id ) eq 'Hey'} ?
Related
I want to know what the counterpart is in Ruby for this kind of expression:
var status=false;
var xx=new Obj(xx,status?"0":"1",status?"2":"3");
I tried the same in Ruby, but it seems that the syntax:
status?"23":nil
does not work.
Method names can end with question marks, so use more spaces:
status ? "23" : nil
Equivalently you could write:
("23" if status)
Put a space between status and ?. Seems that it might get parsed as a method name status?. Also, don't terminate your sentences with semicolons. And don't use var.
x = status ? "0" : "1"
I get an "Expected Identifier" message against the if line. Any ideas why?
if ([inputA.text isEqualToString:#""]) && ([inputB.text <> isEqualToString:#""]) {
c = 1;
}
I'm trying to say it both inputs are empty...
I presume there isn't an easier way to say if the text is null in Obj C++?
An if statement requires that its condition expression be enclosed in parentheses. You have a compound expression. You've used parentheses around the subexpressions of the logical AND operation (&&), but you haven't surrounded the entire expression in parentheses. (The subexpressions don't actually require parentheses in this case, but they don't hurt.)
Next, you have a random <> in the second subexpression. What is that doing in there? In some languages that is the "not equal" operator, but a) it's not an operator in C or Objective-C, b) it wouldn't go inside a message-send expression like that, and c) you claim you were trying to check that both inputs are empty, so I wouldn't expect you to try to negate the test for equality with the empty string.
So, fixing just those problems yields:
if ([inputA.text isEqualToString:#""] && [inputB.text isEqualToString:#""]) {
c = 1;
}
That said, pie's answer is good, too. It also works if either of the inputs has a nil text property, too.
if ([inputA.text length]==0 && [inputB.text length]==0)
{
c = 1;
}
What I'm trying to do:
result = (not question?) \
and ( \
condition \
or ( \
comparer == compared and another_question? \
) \
)
The goal is to have complicated and / or logic and still have it be readable.
The problem with the above attempted syntax is that it some how messes up parenthesis in ruby's parser, so console says that the error is in a file that this code isn't in. (though it's in the call stack)
without the back slashes, I get these:
syntax error, unexpected kAND, expecting kEND (SyntaxError)
and
syntax error, unexpected kOR, expecting ')'
any ideas on how to properly do this?
Remove the space after the backslash in another_question? \. You're escaping the space rather than the newline, which causes a syntax error.
Note you don't need to escape every newline.
result = (not question?) \
and (
condition \
or (
comparer == compared and another_question?
)
)
For logical expression, you should use &&, ||, !, not and, or, not.
and, or, not should only be used for control-flow.
One reason is that &&, ||, ! have higher precedence than and, or, not.
Read more about this in this blog post.
Make sure each line (except the last) ends with an operator so the interpreter "knows" there will be more operands coming, e.g.
result = (not question?) and (
condition or
(comparer == compared and another_question?)
)
(tested with MRI 1.8.7)
Try this:
sub = (comparer == compared and another_question?)
result = (not question?) and (condition or sub)
No need to make the whole thing one expression.
I actually have a string called "cond". This is the content of that string:
"20 < 50"
I would like to insert it into a condition like this: (example)
if 20 < 50
return "Hello"
But that condition is a string, so I can't write this:
if cond
return "Hello"
So I would like to know if it is possible to convert a string to a condition to set in an "if" condition. And if it is possible, how can I do it ?
Thank you.
eval might just be your friend here:
>> eval('20 < 50')
=> true
However, eval will execute the arbitrary code inside its argument; you should be sure that your cond can't contain anything detrimental to your system's health!
One alternative to using eval is perhaps to write an evaluator (or use/modify an existing one, like this one by Sterling Camden).
As is his code requires you to write lt, gt, eq, and so on, instead of <, >, ==, ... . As noted in a comment in calc.rb:
# Equality and its clan (note we cannot use '==' or other two-character
# non-word operators, because of the way we parse the string. Non-word
# characters come in one at a time.
If you know the condition will always be basic like the example you provided, you can do this:
left, op, right = "20 < 50".split
cond = left.to_i.send(op.to_sym, right.to_i)
I want to search div id in an html doc with certain pattern.
I want to match this pattern in regex:
foo_([[:digit:]]{1.8})
using xpath. What is the xpath equivalent for the above pattern?
I'm stuck with //div[#id="foo_ and then what? If someone could continue a legal expression for it.
EDIT
Sorry, I think I have to elaborate more. Actually it's not foo_, it's post_message_
Btw, I use mechanize/nokogiri ( ruby )
Here's the snippet :
html_doc = Nokogiri::HTML(open(myfile))
message_div = html_doc.xpath('//div[substring(#id,13) = "post_message_" and substring-after(#id, "post_message_") => 0 and substring-after(#id, "post_message_") <= 99999999]')
Still failed. Error message:
Couldn't evaluate expression '//div[substring(#id,13) = "post_message_" and substring-after(#id, "post_message_") => 0 and substring-after(#id, "post_message_") <= 99999999]' (Nokogiri::XML::XPath::SyntaxError)
How about this (updated):
XPath 1.0:
"//div[substring-before(#id, '_') = 'foo'
and substring-after(#id, '_') >= 0
and substring-after(#id, '_') <= 99999999]"
Edit #2: The OP made a change to the question. The following, even more reduced XPath 1.0 expression works for me:
"//div[substring(#id, 1, 13) = 'post_message_'
and substring(#id, 14) >= 0
and substring(#id, 14) <= 99999999]"
XPath 2.0 has a convenient matches() function:
"//div[matches(#id, '^foo_\d{1,8}$')]"
Apart from the better portability, I would expect the numerical expression (XPath 1.0 style) to perform better than the regex test, though this would only become noticeable when processing large data sets.
Original version of the answer:
"//div[substring-before(#id, '_') = 'foo'
and number(substring-after(#id, '_')) = substring-after(#id, '_')
and number(substring-after(#id, '_')) >= 0
and number(substring-after(#id, '_')) <= 99999999]"
The use of the number() function is unnecessary, because the mathematical comparison operators coerce their arguments to numbers implicitly, any non-numbers will become NaN and the greater than/less than tests will fail.
I also removed the encoding of the angle brackets, since this is an XML requirement, not an XPath requirement.
As already pointed out, in XPath 2.0 it would be good to use its standard regex capabilities with a function like the matches() function.
One possible XPath 1.0 solution:
//div[starts-with(#id, 'post_message_')
and
string-length(#id) = 21
and
translate(substring-after(#id, 'post_message_'),
'0123456789',
''
)
=
''
]
Do note the following:
The use of the standard XPath function starts-with().
The use of the standard XPath function string-length().
The use of the standard XPath function substring-after().
The use of the standard XPath function translate().
Or use xpath function matches(string,pattern).
<xsl:if test="matches(name(.),'foo_')">
Unfortunately it's not regex, but it might be enough unless you have other foo_ tags you don't need, then I Guess you can add a few more "if" checks to cull them out.
Nikkou makes this very easy and readable:
doc.search('div').attr_matches('id', /post_message_\d{1,8}/)