How to get float number in Lua from IUP text entry - lua

I am trying following simple code to get a decimal value from user:
require( "iuplua" )
t1 = iup.text{expand = "YES", padding = "10x10", alignment="ARIGHT", size="40x"}
btn = iup.button {title = "Print:", padding = "10x10", alignment="ACENTER", size="40x"}
qbtn = iup.button{title="Quit", expand = "YES", padding = "10x10", alignment="ACENTER", size="40x"}
function btn:action()
strval1 = string.match (t1.value, "%d+")
print (strval1)
num = tonumber(strval1)
print (num)
end
function qbtn:action()
os.exit()
end
dlg = iup.dialog {
iup.vbox{
iup.hbox{
iup.label{title="Decimal:", padding = "10x10", alignment="ALEFT", size="40x"},
t1 },
iup.hbox{
btn,
qbtn }}}
dlg:show()
iup.MainLoop()
However, it prints out only an integer number (part before decimal- even 25.9999 prints as 25).
How can I get float or decimal value entered by user? Thanks for your help.

The problem with the code is that the pattern "%d+" in btn:action only gets the first run of digits.
You can change the pattern to handle decimal points, but it is hard to write a pattern that works in all cases, including optional sign and decimal point and scientific format.
It is best to let tonumber do its work: it will return nil if the string cannot be converted to a number.

Another option is to use the MASK attribute of the IupText to let the user only be able to enter numbers.

Related

How do I use more then one pattern for gmatch

Hello I am trying to get some data from a text file and put it into a table.
Im not sure how to add more then one pattern while also doing what I want, I know this pattern by its self %a+ finds letters and %b{} finds brackets, but I am not sure how to combine them together so that I find the letters as a key and the brackets as a value and have them be put into a table that I could use.
text file :
left = {{0,63},{16,63},{32,63},{48,63}}
right = {{0,21},{16,21},{32,21},{48,21}}
up = {{0,42},{16,42},{32,42},{48,42}}
down = {{0,0},{16,0},{32,0},{48,0}}
code:
local function get_animations(file_path)
local animation_table = {}
local file = io.open(file_path,"r")
local contents = file:read("*a")
for k, v in string.gmatch(contents, ("(%a+)=(%b{})")) do -- A gets words and %b{} finds brackets
animation_table[k] = v
print("key : " .. k.. " Value : ".. v)
end
file:close()
end
get_animations("Sprites/Player/MainPlayer.txt")
This is valid Lua code, why not simply execute it?
left = {{0,63},{16,63},{32,63},{48,63}}
right = {{0,21},{16,21},{32,21},{48,21}}
up = {{0,42},{16,42},{32,42},{48,42}}
down = {{0,0},{16,0},{32,0},{48,0}}
If you don't want the data in globals, use the string library to turn it into
return {
left = {{0,63},{16,63},{32,63},{48,63}},
right = {{0,21},{16,21},{32,21},{48,21}},
up = {{0,42},{16,42},{32,42},{48,42}},
down = {{0,0},{16,0},{32,0},{48,0}},
}
befor you execute it.
If you insist on parsing that file you can use a something like this for each line:
local line = "left = {{0,63},{16,63},{32,63},{48,63}}"
print(line:match("^%w+"))
for num1, num2 in a:gmatch("(%d+),(%d+)") do
print(num1, num2)
end
This should be enough to get you started. Of course you wouldn't print those values but put them into a table.

Getting a specific number from a bigger number?

a = (any random number)
Is there a way could I get the third number (12345) without converting it into a string?
If not, what would be a good way to get it by converting it into a string?
You can use the sub function
function getDigit(value,digitPlace)
return tonumber(tostring(value):sub(digitPlace,digitPlace))
end
This will get the third digit of a as a number:
a = 12345
print(getDigit(a,3))
You can get that using simple maths.
function getDigitInt(value, digit)
-- get rid of the sign
value = math.abs(value)
-- how many digits does the number have?
local numDigits = math.floor(math.log(value, 10)) + 1
-- does the requested digit exist?
if digit > numDigits or digit < 1 then
print("digit does not exist")
return
end
-- return the requested digit
return math.floor(value / 10^(numDigits - digit)) % 10
end
-- test
for i = 0, 8 do print(getDigitInt(1234567, i)) end
Add more error handling as needed. Also this can only handle integers of course. But I'm sure you will find out how to apply this idea to decimals as well.
You can convert the number into array and find the any place easily like blow
public int GetDigitsPlace(int number, int digitPlace) {
string t = number.ToString();
int[] nArr = new int[t.Length];
for(int i = 0; i < nArr.Length; i++) {
nArr[i] = int.Parse(t[i]);
}
return nArr[digitPlace];
}

Lua unusual variable name (question mark variable)

I have stumbled upon this line of code and I am not sure what the [ ? ] part represents (my guess is it's a sort of a wildcard but I searched it for a while and couldn't find anything):
['?'] = function() return is_canadian and "eh" or "" end
I understand that RHS is a functional ternary operator. I am curious about the LHS and what it actually is.
Edit: reference (2nd example):
http://lua-users.org/wiki/SwitchStatement
Actually, it is quite simple.
local t = {
a = "aah",
b = "bee",
c = "see",
It maps each letter to a sound pronunciation. Here, a need to be pronounced aah and b need to be pronounced bee and so on. Some letters have a different pronunciation if in american english or canadian english. So not every letter can be mapped to a single sound.
z = function() return is_canadian and "zed" or "zee" end,
['?'] = function() return is_canadian and "eh" or "" end
In the mapping, the letter z and the letter ? have a different prononciation in american english or canadian english. When the program will try to get the prononciation of '?', it will calls a function to check whether the user want to use canadian english or another english and the function will returns either zed or zee.
Finally, the 2 following notations have the same meaning:
local t1 = {
a = "aah",
b = "bee",
["?"] = "bee"
}
local t2 = {
["a"] = "aah",
["b"] = "bee",
["?"] = "bee"
}
If you look closely at the code linked in the question, you'll see that this line is part of a table constructor (the part inside {}). It is not a full statement on its own. As mentioned in the comments, it would be a syntax error outside of a table constructor. ['?'] is simply a string key.
The other posts alreay explained what that code does, so let me explain why it needs to be written that way.
['?'] = function() return is_canadian and "eh" or "" end is embedded in {}
It is part of a table constructor and assigns a function value to the string key '?'
local tbl = {a = 1} is syntactic sugar for local tbl = {['a'] = 1} or
local tbl = {}
tbl['a'] = 1
String keys that allow that convenient syntax must follow Lua's lexical conventions and hence may only contain letters, digits and underscore. They must not start with a digit.
So local a = {? = 1} is not possible. It will cause a syntax error unexpected symbol near '?' Therefor you have to explicitly provide a string value in square brackets as in local a = {['?'] = 1}
they gave each table element its own line
local a = {
1,
2,
3
}
This greatly improves readability for long table elements or very long tables and allows you maintain a maximum line length.
You'll agree that
local tbl = {
z = function() return is_canadian and "zed" or "zee" end,
['?'] = function() return is_canadian and "eh" or "" end
}
looks a lot cleaner than
local tbl = {z = function() return is_canadian and "zed" or "zee" end,['?'] = function() return is_canadian and "eh" or "" end}

VALUE! Ignore text in excel cell calculation

I often run into VALUE! errors in my calculations because they contain numbers and text. How can I leave the text in the cell and proceed with the calculation?
For example:
cell A1 contents look like this: 101.1 J
cell A2 contents look like this: 500 U
cell A3 contents look like this: 0.2
If I want to add A1+A2+A3 into cell A4, how can I ignore the J and U to calculate 101.1+500+0.2 to get 602.3 in cell A4?
Thanks!
You need extract the values from the strings - and this can only be done if you have some kind of information about the format to the numbers. In your example, you could place the following formula in B1:B3 and then add a =SUM(B1:B3):
=IF(ISNUMBER(A1),A1,VALUE(LEFT(A1,SEARCH(" ",A1)-1)))
The above formula will extract the number and convert it to a value - unless it was already a number.
Using Custom Function
Place below code in Standard Module
Function add_num(cell1, ParamArray Arr() As Variant)
Dim temp As Double
For i = LBound(Arr) To UBound(Arr)
temp = temp + GetNumber(Arr(i))
Next
add_num = GetNumber(cell1.Value) + temp
End Function
Function GetNumber(ByVal str As String) As Double
Dim objRegEx As Object
Set objRegEx = CreateObject("VBScript.RegExp")
objRegEx.IgnoreCase = True
objRegEx.Global = True
objRegEx.Pattern = "\d{1,2}([\.,][\d{1,2}])?"
Set allMatches = objRegEx.Execute(str)
For i = 0 To allMatches.Count - 1
result = result & allMatches.Item(i)
Next
GetNumber = result
End Function
add_num function can be called from excel interface using =addnum(<cells>). It accepts multiple cells.

How Lua tables work

I am starting to learn Lua from Programming in Lua (2nd edition)
I didn't understand the following in the book. Its very vaguely explained.
a.) w={x=0,y=0,label="console"}
b.) x={math.sin(0),math.sin(1),math.sin(2)}
c.) w[1]="another field"
d.) x.f=w
e.) print (w["x"])
f.) print (w[1])
g.) print x.f[1]
When I do print(w[1]) after a.), why doesn't it print x=0
What does c.) do?
What is the difference between e.) and print (w.x)?
What is the role of b.) and g.)?
You have to realize that this:
t = {3, 4, "eggplant"}
is the same as this:
t = {}
t[1] = 3
t[2] = 4
t[3] = "eggplant"
And that this:
t = {x = 0, y = 2}
is the same as this:
t = {}
t["x"] = 0
t["y"] = 2
Or this:
t = {}
t.x = 0
t.y = 2
In Lua, tables are not just lists, they are associative arrays.
When you print w[1], then what really matters is line c.) In fact, w[1] is not defined at all until line c.).
There is no difference between e.) and print (w.x).
b.) creates a new table named x which is separate from w.
d.) places a reference to w inside of x. (NOTE: It does not actually make a copy of w, just a reference. If you've ever worked with pointers, it's similar.)
g.) Can be broken up in two parts. First we get x.f which is just another way to refer to w because of line d.). Then we look up the first element of that table, which is "another field" because of line c.)
There's another way of creating keys in in-line table declarations.
x = {["1st key has spaces!"] = 1}
The advantage here is that you can have keys with spaces and any extended ASCII character.
In fact, a key can be literally anything, even an instanced object.
function Example()
--example function
end
x = {[Example] = "A function."}
Any variable or value or data can go into the square brackets to work as a key. The same goes with the value.
Practically, this can replace features like the in keyword in python, as you can index the table by values to check if they are there.
Getting a value at an undefined part of the table will not cause an error. It will just give you nil. The same goes for using undefined variables.
local w = {
--[1] = "another field"; -- will be set this value
--["1"] = nil; -- not save to this place, different with some other language
x = 0;
y = 0;
label = "console";
}
local x = {
math.sin(0);
math.sin(1);
math.sin(2);
}
w[1] = "another field" --
x.f = w
print (w["x"])
-- because x.f = w
-- x.f and w point one talbe address
-- so value of (x.f)[1] and w[1] and x.f[1] is equal
print (w[1])
print ((x.f)[1])
print (x.f[1])
-- print (x.f)[1] this not follows lua syntax
-- only a function's has one param and type of is a string
-- you can use print "xxxx"
-- so you print x.f[1] will occuur error
-- in table you can use any lua internal type 's value to be a key
-- just like
local t_key = {v=123}
local f_key = function () print("f123") end
local t = {}
t[t_key] = 1
t[f_key] = 2
-- then t' key actualy like use t_key/f_key 's handle
-- when you user t[{}] = 123,
-- value 123 related to this no name table {} 's handle

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