i have some prblm while checking the conditions using if statement in verilog code. it also similar to c. but in my coding it compares many strings using multiple if . it check if true the condition below the if statement will work. in case if more strings are matched it execute all the true blocks.if there is no match it goes to else...so is any possible in verilog for multiple if with single else....here we not able to use case because the condition is comparision.
Cascaded if statements:
always #* begin
if ( ... ) begin
// ...
end
else if ( ... ) begin
// ...
end
else begin
// ...
end
end
Often the case statement is a better approach:
always #* begin
case ( reg_or_wire )
0 : begin
// ...
end
1 : begin
// ...
end
default : begin
// ...
end
endcase
end
The case values are integer by default but you should probably specify width and value, e.g. 4'b1010, 4'ha;
Related
For removing everything between parentheses, currently i use:
SELECT
REGEXP_REPLACE('(aaa) bbb (ccc (ddd) / eee)', "\\([^()]*\\)", "");
Which is incorrect, because it gives bbb (ccc / eee), as that removes inner parentheses only.
How to remove everynting between nested parentheses? so expected result from this example is bbb
In case of Google BigQuery, this is only possible if you know your maximum number of nestings. Because it uses re2 library that doesn't support regex recursions.
let r = /\((?:(?:\((?:[^()])*\))|(?:[^()]))*\)/g
let s = "(aaa) bbb (ccc (ddd) / eee)"
console.log(s.replace(r, ""))
If you can iterate on the regular expression operation until you reach a fixed point you can do it like this:
repeat {
old_string = string
string := remove_non_nested_parens_using_regex(string)
} until (string == old_string)
For instance if we have
((a(b)) (c))x)
on the first iteration we remove (b) and (c): sequences which begin with (, end with ) and do not contain parentheses, matched by \([^()]*\). We end up with:
((a) )x)
Then on the next iteration, (a) is gone:
( )x)
and after one more iteration, ( ) is gone:
x)
when we try removing more parentheses, there is no more change, and so the algorithm terminates with x).
for(i=getchar();; i=getchar())
if(i=='x')
break;
else putchar(i);
Answer is : mi
Can someone explain this piece of code ?(MCQ Question)
This question can be solved by eliminating incorrect answer. This fragments prints character and exits loop if the character is an x. So the program would not output an x.
Any output string that doesn't contain x is possible. In your MCQ, possibly mi is the only option with x and all other options contain x somewhere in the string making them incorrect answer.
If input is "mix....", output would be "mi". Below is your loop unrolled.
getchar() -> m -> else -> print m /* First getchar */
getchar() -> i -> else -> print i /* Second getchar */
getchar() -> x -> if -> break /* Second getchar */
for(i=getchar();; i=getchar())
if(i=='x')
break;
else putchar(i);
your Code will keep on running till it encounter 'x' so whatever input you give, it will read character by character as you have used getchar() function..
If character is 'x' then break the loop.
else print character.
like, If the input is
sparx
output will be
spar
The for loop
for(i=getchar();; i=getchar())
and syntax and structure of the for loop is
for ( variable initialization; condition; variable update )
as i = getchar() will read char 'i' it is ok. next there is no condition and final in updating you are again reading a character so it a infinite loop.
Loop will terminate only when it will encounter 'x' as the statement
if(i=='x')
break;
Otherwise it will keep on printing the character.
else putchar(i);
Here is the Demo.
Hope it helps!!
The "single line if statement" exists in C# and VB.NET as in many other programming and script languages in the following format
lunchLocation = (dayOfTheWeek == "Tuesday") ? "Fuddruckers" : "Food Court";
does anyone know if there is even in VBScript and what's the extact syntax?
The conditional ternary operator doesn't exist out of the box, but it's pretty easy to create your own version in VBScript:
Function IIf(bClause, sTrue, sFalse)
If CBool(bClause) Then
IIf = sTrue
Else
IIf = sFalse
End If
End Function
You can then use this, as per your example:
lunchLocation = IIf(dayOfTheWeek = "Tuesday", "Fuddruckers", "Food Court")
The advantage of this over using a single line If/Then/Else is that it can be directly concatenated with other strings. Using If/Then/Else on a single line must be the only statement on that line.
There is no error checking on this, and the function expects a well formed expression that can be evaluated to a boolean passed in as the clause. For a more complicated and comprehensive answer see below. Hopefully this simple response neatly demonstrates the logic behind the answer though.
It's also worth noting that unlike a real ternary operator, both the sTrue and sFalse parameters will be evaluated regardless of the value of bClause. This is fine if you use it with strings as in the question, but be very careful if you pass in functions as the second and third parameters!
VBScript does not have any ternary operator.
A close solution in a single line and without using a user defined function, pure VBScript:
If dayOfTheWeek = "Tuesday" Then lunchLocation = "Fuddruckers" Else lunchLocation = "Food Court"
BTW, you can use JScript in Classic ASP if ternary opertor is so important to you.
edited 2017/01/28 to adapt to some of the non boolean condition arguments
Note: If all you need is to select an string based on an boolean value, please, use the code in the Polinominal's answer. It is simpler and faster than the code in this answer.
For a simple but more "flexible" solution, this code (the original code in this answer) should handle the usual basic scenarios
Function IIf( Expression, TruePart, FalsePart)
Dim bExpression
bExpression = False
On Error Resume Next
bExpression = CBool( Expression )
On Error Goto 0
If bExpression Then
If IsObject(TruePart) Then
Set IIf = TruePart
Else
IIf = TruePart
End If
Else
If IsObject(FalsePart) Then
Set IIf = FalsePart
Else
IIf = FalsePart
End If
End If
End Function
If uses the Cbool function to try to convert the passed Expression argument to a boolean, and accepts any type of value in the TrueValue and FalseValue arguments. For general usage this is fast, safe and fully complies to documented VBScript behaviour.
The only "problem" with this code is that the behaviour of the CBool is not fully "intuitive" for some data types, at least for those of us that constantly change between vbscript and javascript. While numeric values are coherent (a 0 is a False and any other numeric value is a True), non numeric types generate a runtime error (in previous code handled as false), except if it is a string with numeric content or that can be interpreted as true or false value in english or in the OS locale.
If you need it, a VBScript version "equivalent" to the ? javascript ternary operator is
Function IIf( Expression, TruePart, FalsePart )
Dim vType, bExpression
vType = VarType( Expression )
Select Case vType
Case vbBoolean : bExpression = Expression
Case vbString : bExpression = Len( Expression ) > 0
Case vbEmpty, vbNull, vbError : bExpression = False
Case vbObject : bExpression = Not (Expression Is Nothing)
Case vbDate, vbDataObject : bExpression = True
Case Else
If vType > 8192 Then
bExpression = True
Else
bExpression = False
On Error Resume Next
bExpression = CBool( Expression )
On Error Goto 0
End If
End Select
If bExpression Then
If IsObject( TruePart ) Then
Set IIf = TruePart
Else
IIf = TruePart
End If
Else
If IsObject( FalsePart ) Then
Set IIf = FalsePart
Else
IIf = FalsePart
End If
End If
End Function
BUT independently of the version used, be careful, you are calling a function, not using a ternary operator. Any code, or function call you put in TruePart of FalsePart WILL BE EXECUTED independently of the value of the condition. So this code
value = IIf( 2 > 3 , DoSomething(), DontDoSomething() )
WILL EXECUTE the two functions. Only the correct value will be returned to value var.
There's a weird trick possible (hi, Python!) for exact one-liner:
lunchLocation = array("Food Court", "Fuddruckers")(-(dayOfTheWeek = "Tuesday"))
The "magic" works because of a boolean operation specifics in VBScript.
True is actually -1 and False is 0, therefore we can use it as an index for array (just get rid of a minus). Then the first item of array will be a value for False condition and second item for True.
related to #MC_ND answer:
to execute only one function, you can do something like that:
If VarType(TruePart) = vbString and InStr(1,TruePart,"function:") = 1 then
IIf = GetRef(Mid(TruePart,10))()
Else
IIf = TruePart
End If
the same for the FalsePart, and call IIf() it like that:
value = IIf( 2 > 3 , "function:DoSomething", "function:DontDoSomething" )
and will call DoSomething() or DontDoSomething()
Assume, I have 2 strings.
$file1_out="astra.abs ::nerve : Costa.br_.cotAlev.ksaf.large.props.fault_check"
$file2_out="astra.abs ::nerve : Costa.br_.cotBlev.ksaf.large.props.fault_check"
You can see that the only difference is A and B in cotAlev & cotBlev in the 2 strings. I would like to compare them and get 2 new variables
$part1="astra.abs ::nerve : Costa.br_."
$part2=".ksaf.large.props.fault_check"
$var="cot_lev" ###removed the mismatching character
That is break till first unequal word and split into 3. How can I do this use regex in PERL
I'm new to perl and used loop concept common in C here to solve this. I've achieved this by breaking strings into characters into comparing each and then combining them accordingly into 3 variables. But i was told that there were easier ways to do this. There are lot of comparisons to be made, so speed does matter...
Have a look at Text::Diff, it may do what you try to do already.
I am not sure how this could be handled with regular expressions. You said you handled this with C looping. You could do something similar in Perl.
my #file1_chars = split //, $file1_out;
my #file2_chars = split //, $file2_out;
This will split up your strings into an array with each entry in the array being a separate character. Now you can loop till you find your first mismatched character:
my $first_mismatched;
for my $char_num ( (0..$#file1_chars) ) {
if ( $file1_chars[$char_num] ne $file2_chars[$char_num] ) {
$first_mismatched = $char_num;
}
}
if ( defined $first_mismatched ) {
say "The two strings stop matching on character # $first_mismatched";
}
This will print out:
The two strings stop matching on character # 34
The $#file1_chars is the last array index of #file1_chars. The (0..$#file1_chars) indexes from the first index entry to the last index entry of #file1_chars.
You could reverse this to go from the last character to the first character:
my $last_mismatched;
for my $char_num ( reverse (0..$#file1_chars) ) {
if ( $file1_chars[$char_num] ne $file2_chars[$char_num] ) {
$last_mismatched = $char_num;
}
}
if ( defined $last_mismatched ) {
say "The two strings restart matching on character # $first_mismatched";
}
I need regex help to create a delphi function to replace the HyperString ParseWord function in Rad Studio XE2. HyperString was a very useful string library that never made the jump to Unicode. I've got it mostly working but it doesn't honor quote delimiters at all. I need it to be an exact match for the function described below:
function ParseWord(const Source,Table:String;var Index:Integer):String;
Sequential, left to right token parsing using a table of single
character delimiters. Delimiters within quoted strings are ignored.
Quote delimiters are not allowed in Table.
Index is a pointer (initialize to '1' for first word) updated by the
function to point to next word. To retrieve the next word, simply
call the function again using the prior returned Index value.
Note: If Length(Resultant) = 0, no additional words are available.
Delimiters within quoted strings are ignored. (my emphasis)
This is what I have so far:
function ParseWord( const Source, Table: String; var Index: Integer):string;
var
RE : TRegEx;
match : TMatch;
Table2,
chars : string;
begin
if index = length(Source) then
begin
result:= '';
exit;
end;
// escape the special characters and wrap in a Group
Table2 :='['+TRegEx.Escape(Table, false)+']';
RE := TRegEx.create(Table2);
match := RE.Match(Source,Index);
if match.success then
begin
result := copy( Source, Index, match.Index - Index);
Index := match.Index+match.Length;
end
else
begin
result := copy(Source, Index, length(Source)-Index+1);
Index := length(Source);
end;
end;
while ( Length(result)= 0) and (Index<length(Source)) do
begin
Inc(Index);
result := ParseWord(Source,Table, Index);
end;
cheers and thanks.
I would try this regex for Table2:
Table2 := '''[^'']+''|"[^"]+"|[^' + TRegEx.Escape(Table, false) + ']+';
Demo:
This demo is more a POC since I was unable to find an online delphi regex tester.
The delimiters are the space (ASCII code 32) and pipe (ASCII code 124) characters.
The test sentence is:
toto titi "alloa toutou" 'dfg erre' 1245|coucou "nestor|delphi" "" ''
http://regexr.com?32i81
Discussion:
I assume that a quoted string is a string enclosed by either two single quotes (') or two double quotes ("). Correct me if I am wrong.
The regex will match either:
a single quoted string
a double quoted string
a string not composed by any passed delimiters
Known bug:
Since I didn't know how ParseWord handle quote escaping inside string, the regex doesn't support this feature.
For instance :
How to interpret this 'foo''bar' ? => Two tokens : 'foo' and 'bar' OR one single token 'foo''bar'.
What about this case too : "foo""bar" ? => Two tokens : "foo" and "bar" OR one single token "foo""bar".
In my original code I was looking for the delimiter and taking everything up to that as my next match, but that concept didn't carry over when looking for something within quotes. #Stephan's suggestion of negating the search eventually lead me to something that works. An additional complication that I never mentioned earlier is that HyperStr can use anything as a quoting character. The default is double quote but you can change it with a function call.
In my solution I've explicitly hardcoded the QuoteChar as double quote, which suits my own purposes, but it would be trivial to make QuoteChar a global and set it within another function. I've also successfully tested it with single quote (ascii 39), which would be the tricky one in Delphi.
function ParseWord( const Source, Table: String; var Index: Integer):string;
var
RE : TRegEx;
match : TMatch;
Table2: string;
Source2 : string;
QuoteChar : string;
begin
if index = length(Source) then
begin
result:= '';
exit;
end;
// escape the special characters and wrap in a Group
QuoteChar := #39;
Table2 :='[^'+TRegEx.Escape(Table, false)+QuoteChar+']*|'+QuoteChar+'.*?'+QuoteChar ;
Source2 := copy(Source, Index, length(Source)-index+1);
match := TRegEx.Match(Source2,Table2);
if match.success then
begin
result := copy( Source2, match.index, match.length);
Index := Index + match.Index + match.Length-1;
end
else
begin
result := copy(Source, Index, length(Source)-Index+1);
Index := length(Source);
end;
while ( Length(result)= 0) and (Index<length(Source)) do
begin
Inc(Index);
result := ParseWord(Source,Table, Index);
end;
end;
This solution doesn't strip the quote chars from around quoted strings, but I can't tell from my own existing code if it should or not, and I can't test using Hyperstr. Maybe someone else knows?