export const getValueFromPsetProperty = (pset: string, property: string) => R.pipe(
R.prop('pSets'),
R.find(R.propEq('name', pset)),
R.propOr([], 'properties'),
R.find(R.propEq('name', property)),
R.propOr(null, 'value'),
R.ifElse(isValueValid, null,R.identity),
);
The last pipe does not work. What I want to do is to pass the value if isValueValid is true. How should I do this?
It doesn't look like you're using R.ifElse correctly. All first three arguments should be functions:
A predicate function
The function to execute if the predicate is true
The function to execute if the predicate is false
So from what you're describing, you want to return the value unchanged if isValueValid returns true. In this case your R.ifElse should be:
R.ifElse(isValueValid, R.identity, someOtherFunction)
You may want to consider R.unless which will run a function only if a predicate is false. If value is valid, then the R.unless returns it unchanged.
R.unless(isValueValid, someFunctionIfValueIsNotValid);
Related
I'm trying to save just a number from a string I get from a paragraph but when I try to asign an alias to it and then check the value it returns undefined. I've tried a few solutions I found but none of those seem to work for me. These are two ways I tried (I tried another one similar to the second one but using split, had same result). The console.log inside of the 'then' doesn't show in the console, and when I try the alias after the code is when I get undefined.
cy.get('p')
.eq(1)
.should('have.text', '/[0-9]+/g')
.as('solNumber')
cy.get('p')
.eq(1)
.invoke('text')
.then((text)=>{
var fullText = text;
var pattern = /[0-9]+/g;
var number = fullText.match(pattern);
console.log(number);
})
.as('solNumber')
Please convert with + operator and return the numeric value if you want numeric type to be stored.
cy.get('p').eq(1)
.invoke('text')
.then(fullText => {
const number = fullText.match(/[0-9]+/);
return +number // text to numeric
})
.as('solNumber')
cy.get('#solNumber')
.should('eq', 42) // numeric type
});
Running your 2nd code on this,
<p>21</p>
<p>42</p>
gives the correct outcome
cy.get('p')
.eq(1)
.invoke('text')
.then((text)=>{
var fullText = text;
var pattern = /[0-9]+/g;
var number = fullText.match(pattern);
console.log(number); // logs 42
})
.as('solNumber')
cy.get('#solNumber')
.should('eq', '42') // passes
So, you need to inspect the DOM, it looks like it's not what you expect.
The first attempt you were passing a jquery element to the .should() and although some chainers change the subject yours did not so it saved the jquery element as solNumber.
The second attempt invokes the .text() which was passed to the .then() it logs the number correctly. However, you did not return anything at the end of the .then() block, therefore, solNumber should hold the entire paragraph.
This should help you out to extract the specific number and save it as an alias.
cy.get('p')
.invoke('text')
.invoke('trim')
.then(paragraph => {
const matcher = /some/
expect(paragraph).to.match(matcher) // check number is there
const indexOfText = paragraph.match(matcher) // get index of match text
return paragraph.substring(indexOfText.index, indexOfText.index + indexOfText[0].length) // return substring
})
.as('savedText')
cy.get('#savedText')
.then(cy.log) // will print out the number you seek
I'm just learning while doing ramda.js. Well, there are many ways to reach a goal with ramda, but there is on thing I do not understand.
I would like to check the input for an array of strings that all match one regular expression. I thought I could do it R.all(R.both(isString, isRegExp)), but it seems to deliver a true when the input is a number.
As expected R.allPass([isString, isRegExp]) gives a false with a number input.
But can anyone please explain me why R.all is returning a true? Or what and where is mistake (in thinking)?
Complete code:
var isString = R.is(String),
isMyRegExp = R.test(/^[a-z]+$/),
isMyRegExpString = R.both(isString, isMyRegExp),
isArrayOfMyRegExpStrings = R.all(isMyRegExpString),
isArrayOfMyRegExpStringsPass = R.allPass([isString, isMyRegExp]),
result = {
'all': isArrayOfMyRegExpStrings(9),
'allPass': isArrayOfMyRegExpStringsPass(9)
};
console.log(result);
// {
// all: true,
// allPass: false
// }
https://codepen.io/Eisenhardt/pen/PKLZqj
PS:
I know that I could shorten conditions with just the regexp, but there could be other situations where I need both conditions to be true. eg. isArrayOfNumber and sumOfNumbersOver50.
The second argument to R.all is expecting a list of values to test. Due to the way the function is implemented it is treating the 9 in your example as an empty list, resulting in a vacuous truth and evaluating to true.
I have the following Class
local PROGRESS = {}
PROGRESS.__index = function(self,key)
if key~="__group" and self.__group[key] then
return self.__group[key]
else
return rawget(self,key)
end
end
What this does is when You access table[key] it performs a lookup in table.__group (which is an object of another class) and returns table.__group[key] ,if it is not nil.
Now I am trying to do the same for member functions.
i.e If I call table:key() a lookup must be performed in table.__group and if the function is present, then table.__group:key() should be called.
How do I accomplish this?
I tried to do this.
local PROGRESS = {}
PROGRESS.__index = function(self,key)
if key~="__group" and self.__group[key] then
local val = self.__group[key]
if type(val) == "function" then
self.__group:val()
return function() end
end
return self.__group[key]
else
return rawget(self,key)
end
end
But there are 2 things wrong here.
I am unable to retrieve the original function's arguments
Event if I just ACCESS table[key].function without calling it, the function will be called
And I've got the feeling that I am trying to complicate things and the solution is way simpler.
Any help is appreciated.
UPDATE
#Mud
The problem with the original code is that the object passed as 'self' to the member function is an object of the new class. Not of the old class.
Consider this code
GROUP_CLASS = {}
GROUP_CLASS.__index = GROUP_CLASS
function GROUP_CLASS:showSum (a,b) print(self);print(a + b) end
group_object = setmetatable({},GROUP_CLASS)
group_object:showSum(1,2)
local PROGRESS_CLASS = {}
PROGRESS_CLASS.__index = function(self,key,value)
if key~="__group" and self.__group[key] then
return self.__group[key]
else
return rawget(self,key)
end
end
progress_object = setmetatable( {__group = group_object} , PROGRESS_CLASS)
progress_object:showSum(3,3)
--progress_object is passed as first argument to showSum. But i need group_object to be passed
In the above code, When progress_object:showSum(3,3) is called,
is it possible to pass group_object (or in other words progress_object.__group) as self instead of progress_object.
Hope that makes sense.
Response to updated post:
progress_object is passed as first argument to showSum. But i need group_object to be passed
If you're going to ignore the state of the object a method is called on, and substitute the state of some other object, why is it even a method on that object? That's like overriding the addition operator to do multiplication, a recipe for confusion.
In other words, you want this:
progress_object:method("foo")
To resolve, via bizarre internal machinery, into this:
group_object:method("foo")
Why not skip a step and just make the latter call?
If you must, you could achieve this by returning a proxy for the method which replaces self with __group
local PROGRESS_CLASS = {}
PROGRESS_CLASS.__index = function(self,key)
local groupval = self.__group[key]
if key == '__group' or not groupval then
return rawget(self,key)
elseif type(groupval) ~= 'function' then
return groupval
else
return function(...)
if self == ... then -- method call
-- replace self argument with __group
return groupval(self.__group,select(2,...))
else
return groupval(...)
end
end
end
end
Response to original post:
How I am trying to do the same for member functions. i.e If I call table:key() a lookup must be performed in table.__group and if the function is present, then table.__group:key() should be called.
How do I accomplish this?
Do nothing. Your original code handles this.
Lua doesn't know what a "member function" is. A member is a member (i.e. an element in a table), and whether the value of that member is a function is irrelevant.
Remember:
obj:method(a,b,c) is exactly equivalent to obj.method(obj,a,b,c)
obj.method is exactly equivalent to obj["method"].
Your code already resolves obj["method"] into obj.__group["method"]
So you're done.
For instance, say we have:
group = {}
function group:showSum (a,b) print(a + b) end
function group:showProduct(a,b) print(a * b) end
Using your first code, we can write:
foo = setmetatable({__group = group}, PROGRESS)
foo:showSum(3,3) -- 6
foo:showProduct(3,3) -- 9
That's it.
Now, as long as we're here, let's look at what your second function is doing:
local val = self.__group[key]
if type(val) == "function" then
self.__group:val()
return function() end
end
First you grab the function value from __group. At this point you're done. Simply return that value, and the caller is going to call that value (i.e. (...)). Instead, you call __group["val"] which is likely a totally different function from __group[key] (unless key=="val"), then you pass the caller a function which does nothing.
Is it possible in lua to execute a function from a string representing its name?
i.e: I have the string x = "foo", is it possible to do x() ?
If yes what is the syntax ?
To call a function in the global namespace (as mentioned by #THC4k) is easily done, and does not require loadstring().
x='foo'
_G[x]() -- calls foo from the global namespace
You would need to use loadstring() (or walk each table) if the function in another table, such as if x='math.sqrt'.
If loadstring() is used you would want to not only append parenthesis with ellipse (...) to allow for parameters, but also add return to the front.
x='math.sqrt'
print(assert(loadstring('return '..x..'(...)'))(25)) --> 5
or walk the tables:
function findfunction(x)
assert(type(x) == "string")
local f=_G
for v in x:gmatch("[^%.]+") do
if type(f) ~= "table" then
return nil, "looking for '"..v.."' expected table, not "..type(f)
end
f=f[v]
end
if type(f) == "function" then
return f
else
return nil, "expected function, not "..type(f)
end
end
x='math.sqrt'
print(assert(findfunction(x))(121)) -->11
I frequently put a bunch of functions in a table:
functions = {
f1 = function(arg) print("function one: "..arg) end,
f2 = function(arg) print("function two: "..arg..arg) end,
...,
fn = function(arg) print("function N: argh") end,
}
Then you can use a string as an table index and run your function like this
print(functions["f1"]("blabla"))
print(functions["f2"]("blabla"))
This is the result:
function one: blabla
function two: blablablabla
I find this to be cleaner than using loadstring(). If you don't want to create a special function table you can use _G['foo'].
loadstring is not the answer here. For starters you would need a return in the string, and other details I won't go into.
THC4k has the right idea; if you have the function name in the variable x, then the call you want is
_G[x](arg1, arg2, ...)
Names are not unique, there can be many functions names foo in different namespaces. But _G['foo'] is foo in the global namespace.
It sounds like you want to do an 'eval', which is supported in Lua like so:
assert(loadstring(x))()
You'll probably want to concatenate the "()" onto x first, though.
I got this parameter:
$objDbCmd.Parameters.Add("#telephone", [System.Data.SqlDbType]::VarChar, 18) | Out-Null;
$objDbCmd.Parameters["#telephone"].Value = $objUser.Telephone;
Where the string $objUser.Telephone can be empty. If it's empty, how can I convert it to [DBNull]::Value?
I tried:
if ([string]:IsNullOrEmpty($objUser.Telephone)) { $objUser.Telephone = [DBNull]::Value };
But that gives me the error:
Exception calling "ExecuteNonQuery" with "0" argument(s): "Failed to convert parameter value from a ResultPropertyValueCollection to a String."
And if I convert it to a string, it inserts an empty string "", and not DBNull.
How can this be accomplished?
Thanks.
In PowerShell, you can treat null/empty strings as a boolean.
$x = $null
if ($x) { 'this wont print' }
$x = ""
if ($x) { 'this wont print' }
$x = "blah"
if ($x) { 'this will' }
So.... having said that you can do:
$Parameter.Value = $(if ($x) { $x } else { [DBNull]::Value })
But I'd much rather wrap this up in a function like:
function CatchNull([String]$x) {
if ($x) { $x } else { [DBNull]::Value }
}
I don't know about powershell, but in C# I would do something like this:
if ([string]::IsNullOrEmpty($objUser.Telephone))
{
$objDbCmd.Parameters["#telephone"].Value = [DBNull]::Value;
}
else
{
$objDbCmd.Parameters["#telephone"].Value = $objUser.Telephone;
}
Always append +"" at the end of db values...
$command.Parameters["#EmployeeType"].Value= $ADResult.EmployeeType + ""
Many years later, let me clarify:
Josh's answer shows a helpful simplification for testing strings for emptiness (relying on PowerShell's implicit to-Boolean conversion[1]), but it is unrelated to Tommy's (the OP's) problem.
Instead, the error message
"Failed to convert parameter value from a ResultPropertyValueCollection to a String."
implies that it is the non-null case that caused the problem, because $objDbCmd.Parameters["#telephone"].Value expects either a string value or [DBNull]::Value, whereas $objUser.Telephone is of type [ResultPropertyValueCollection], i.e. a collection of values.
Thus, in the non-null case, a string value must be assigned, which must be derived from the collection; one option is to take the first collection element's value, another would be to join all values with a separator to form a single string, using, e.g., [string]::Join(';', $objUser.Telephone) or, if joining the elements with spaces is acceptable (not a good idea with multiple phone numbers), simply with "$($objUser.Telephone)".[2]
Detecting an empty collection via [string]:IsNullOrEmpty() actually worked, despite the type mismatch, due to how PowerShell implicitly stringifies collections when passing a value to a [string] typed method parameter.[2]
Similarly, using implicit to-Boolean conversion works as expected with collections too: an empty collection evaluates to $false, a non-empty one to $true (as long as there are either at least two elements or the only element by itself would be considered $true[1])
Therefore, one solution is to use the first telephone number entry:
$objDbCmd.Parameters["#telephone"].Value = if ($objUser.Telephone) {
$objUser.Telephone[0].ToString() # use first entry
} else {
[DBNull]::Value
}
Note: If $objUser.Telephone[0] directly returns a [string], you can omit the .ToString() call.
In PowerShell v7+ you can alternatively shorten the statement via a ternary conditional:
$objDbCmd.Parameters["#telephone"].Value =
$objUser.Telephone ? $objUser.Telephone[0].ToString() : [DBNull]::Value
[1] For a comprehensive summary of PowerShell's automatic to-Boolean conversions, see the bottom section of this answer.
[2] When implicitly converting a collection to a string, PowerShell joins the stringified elements of a collection with a single space as the separator by default; you can override the separator with the automatic $OFS variable, but that is rarely done in practice; e.g., array 'foo', 'bar' is converted to 'foo bar'; note that this conversion does not apply when you call the collection's .ToString() method explicitly, but it does apply inside expandable (interpolating) strings, e.g., "$array".