I have an input box in the GUI in VisionWorks. The input is treated as a ValueHolder that holds the string I want to traverse and whatnot, but I can't seem to get to that value. Any ideas?
I guess you mean VisualWorks, and yes: lurker is correct aValueHolder value will do.
However, if your input-field has a converter attached, it may not be a ValueHolder but a TypeConverer, which has already converted the string to a number or whatever.
So what is the class of your value-thingy ("treated like" sounds like it could be something else) ?
Related
I have different commands my program is reading in (i.e., print, count, min, max, etc.). These words can also include a number at the end of them (i.e., print3, count1, min2, max6, etc.). I'm trying to figure out a way to extract the command and the number so that I can use both in my code.
I'm struggling to figure out a way to find the last element in the string in order to extract it, in Smalltalk.
You didn't told which incarnation of Smalltalk you use, so I will explain what I would do in Pharo, that is the one I'm familiar with.
As someone that is playing with Pharo a few months at most, I can tell you the sheer amount of classes and methods available can feel overpowering at first, but the environment actually makes easy to find things. For example, when you know the exact input and output you want, but doesn't know if a method already exists somewhere, or its name, the Finder actually allow you to search by giving a example. You can open it in the world menu, as shown bellow:
By default it seeks selectors (method names) matching your input terms:
But this default is not what we need right now, so you must change the option in the upper right box to "Examples", and type in the search field a example of the input, followed by the output you want, both separated by a ".". The input example I used was the string 'max6', followed by the desired result, the number 6. Pharo then gives me a list of methods that match that:
To get what would return us the text part, you can make a new search, changing the example output from number 6 to the string 'max':
Fortunately there is several built-in methods matching the description of your problem.
There are more elegant ways, I suppose, but you can make use of the fact that String>>#asNumber only parses the part it can recognize. So you can do
'print31' reversed asNumber asString reversed asNumber
to give you 31. That only works if there actually is a number at the end.
This is one of those cases where we can presume the input data has a specific form, ie, the only numbers appear at the end of the string, and you want all those numbers. In that case it's not too hard to do, really, just:
numText := 'Kalahari78' select: [ :each | each isDigit ].
num := numText asInteger. "78"
To get the rest of the string without the digits, you can just use this:
'Kalahari78' withoutTrailingDigits. "Kalahari"6
As some of the Pharo "OGs" pointed out, you can take a look at the String class (just type CMD-Return, type in String, hit Return) and you will find an amazing number of methods for all kinds of things. Usually you can get some ideas from those. But then there are times when you really just need an answer!
Given a Julia object of composite type, how can one determine its fields?
I know one solution if you're working in the REPL: First you figure out the type of the object via a call to typeof, then enter help mode (?), and then look up the type. Is there a more programmatic way to achieve the same thing?
For v0.7+
Use fieldnames(x), where x is a DataType. For example, use fieldnames(Date), instead of fieldnames(today()), or else use fieldnames(typeof(today())).
This returns Vector{Symbol} listing the field names in order.
If a field name is myfield, then to retrieve the values in that field use either getfield(x, :myfield), or the shortcut syntax x.myfield.
Another useful and related function to play around with is dump(x).
Before v0.7
Use fieldnames(x), where x is either an instance of the composite type you are interested in, or else a DataType. That is, fieldnames(today()) and fieldnames(Date) are equally valid and have the same output.
suppose the object is obj,
you can get all the information of its fields with following code snippet:
T = typeof(obj)
for (name, typ) in zip(fieldnames(T), T.types)
println("type of the fieldname $name is $typ")
end
Here, fieldnames(T) returns the vector of field names and T.types returns the corresponding vector of type of the fields.
Does anyone know how to override the ParsePrimitive method in DeserializeType?
Basically I have a of Dictionary<string,object> and whenever a number gets parsed in I want it to always be a decimal. Currently it gets taken down to the smallest numeric type it thinks the number will fit into.
Thanks
Added TryToParseNumericType but defaults to decimal
https://github.com/ServiceStack/ServiceStack.Text/pull/347
if user give other than double value like string/alphanumeric/alphabets/some illegal values (ex:1;2), it should not accept as double and give an error message.
how to write it in c++.
thanks in advance
You Usually want to do the conversion with strtod. That will set a pointer to the end of the input that it could convert to a double. After it returns, you can check that to see whether it converted none, part, of all of the input, and react accordingly.
I have an EditText object (et_travel) on my screen that's asking for miles traveled. I grab that data like this:
float travel = Float.parseFloat(et_travel.getText().toString());
if(travel > 40000){
I just discover that if someone puts 40000 in the EditText, everything works fine, but if they put 40,000 (adding a comma to the number), I force close on the float travel = ...statement.
How can I evaluate the number without having a problem from the user adding a comma?
Is this in Java? It appears to be, but I'm wondering if I'm mistaken. Regardless, I would suggest you remove all of the characters from the string that are not of a numeric type. A way to do this may be using a regular expression.
A way to do this in Java may be the following:
String input = et_travel.getText().toString();
input = input.replaceAll("[^0-9]", "");
float travel = Float.parseFloat(input);
...
This way, you strip anything that is a non-numeric value from the string first, and then attempt to do your work. Obviously do some error checking before this (like input is not null and such). One change that is needed however is that you may need to maintain the '.' character (if you're given non-integer values). This would require changing the first regex a bit.
Check here: http://download.oracle.com/javase/1.5.0/docs/api/java/lang/String.html#replaceAll(java.lang.String, java.lang.String)
What you need is some validation on the input. Before converting the string into a float parse the string. If there are any ','s then remove them. If there is just junk then reject the input, otherwise someone could put a word or anything else in the input and cause havoc in your program.
Check out
inputType to restrict user input
android:inputType="number"