I have a list of strings and I want to remove each string from the list that matches any of the regex patterns from another list. I have solved it this way, however, I know there is a better way to do so. For example:
Regex_list := ["^reg\ex1", "/^\d+$/", "^Apple"]
String_list := ["Apple", "Banana", "Pair" "12345"]
Want - {Banana, Pair}
I don't know my regex, but for this example lets say Apple and 12345 match the last 2 on the regex list. I want to have a list only containing Banana and Pair.
My take:
string_list := input.string_list[_]
match := {x | x := string_list; regex.match(data.regex_list[_], x)} --> {Apple, 12345}
dont_match := string_list - match --> {"Banana", "Pair"}
I think that is the best way. Alternatively you could use a rule to build a set of matches, but the principle would be the same.
matches[s] {
r := [`^reg\ex1`, `^\d+$`, `^Apple`][_]
s := ["Apple", "Banana", "Pair", "12345"][_]
regex.match(r, s)
}
Related
The way adding strings and variants behaves in Delphi (10.2 Tokyo) was a complete surprise to me. Can someone provide a reasonable explanation for this "feature" or shall we call it a bug ?
function unexpected: string;
var v: Variant;
begin
result := '3';
v := 2;
result := v + result;
ShowMessage(result); //displays 5, I expected 23
result := '3';
v := 2;
result := result + '-' + v;
ShowMessage(result) //displays -1, I expected 3-2
end;
result := v + result
Delphi's Variant type is a slightly extended version of the Win32 API's VARIANT type and supposed to be compatible with it so long as you do not use any Delphi-specific types. Additionally, when you use Delphi-specific string types, it is supposed to behave like it would with the OLE string type. In the Win32 API, it is specifically documented that adding a string and a number will result in a (numeric) addition, not a string concatenation, that you need to have two string operands to get a string concatenation:
VarAdd:
Condition Result
Both expressions are strings Concatenated
[...]
One expression is numeric and the other a string Addition
[...]
I suspect VarAdd is defined like that to make things easier for VB users.
result := result + '-' + v
Here result + '-' should perform string concatenation since both operands are strings. '3-' + v is then treated as a numeric addition, requiring 3- to be parsed as a number. I believe that since there are contexts in which the sign follows the digits, this parse succeeds and produces -3. Adding 2 to that results in -1.
I use the following function to search a TStringList I am reading from a file.
I know that when I search a value, then the return value I need is always on the line after the one with the item I search.
It has always worked using POS to search, but now the file has been expanded and I have to look for 2 items 'Adresse' and 'Adresse 2'
That gives me an issue since pos finds 'Adresse' in both cases and my data is then wrong.
Is there another method of searching a string for a substring that I don't know of or do I have to make my own.
function FindValue(const aFilename, aSearch: string): string;
var
InfoList: TStringList;
Counter: integer;
begin
InfoList := TStringList.Create;
try
InfoList.LoadFromFile(aFilename);
if InfoList.Count > 0 then
for Counter := 0 to InfoList.Count - 1 do
begin
if Pos(aSearch, Infolist.Strings[Counter]) > 0 then
Result := Infolist.Strings[Counter + 1]
end
else
Result := '';
finally
InfoList.Free;
end;
end;
For info: the input to the TStringList comes from a textfile extracted from a HTML file.
A sample of a file could be:
OZ8HP
Hugo Pedersen
Radioamatør
Nykøbing M
Sendeposition:
Adresse:
Prinsensvej 18
Postnummer:
7900
Bynavn:
Nykøbing M
Antenne højde (m):
Kote (m):?Kote (m):Brugerens/tilladelsesindehaverens øvrige adresseoplysninger så som Stednavn og/eller Postboks. Hjælpetegnet * kan anvendes, som beskrevet i hjælp.
Koordinater:
Geografisk anvendelse:
Frekvensmaske:
Tekniske specifikationer:
Sendeeffekt basisstation:
Sendeeffekt mobile anlæg:
Båndbredde (MHz):
Antal anlæg:
MMSI:
Kaldesignaltype:
Personlig
Frekvenskategori:
Udstedelses-metode:
Intention om overdragelse:
Nej
Udløbsdato:
Brugerdata:
Brugernummer:
956078
Adresse:
Prinsensvej 18
Adresse 2:
Sejerslev
Postnr.:
7900
Bynavn:
Nykøbing M
Kaldesignal-kategori:
Bestået A
It looks to me as though the real mistake is being too lax in your search. Why accept partial matches? It would seem more robust to look for complete matches
if SameText(aSearch, Infolist[Counter]) then
or perhaps to account for leading and trailing whitespace:
if SameText(aSearch, Trim(Infolist[Counter])) then
You'd need to pass 'Adresse:' or 'Adresse 2:' as the search string, or add the colon in the search function.
Use AnsiSameText if you want locale sensitive comparison. Use = if you want case sensitive comparison, etc.
You might pass multiple search strings and be able to loop only once over the file. As it stands you read it twice which seems wasteful. Indeed surely better to operate on a string list and not be coupled to file storage.
You return the last match in the data rather than the first, for instance. What if there are multiple matches? Does your code behave as intended?
You should also be aware that if no match is found your function does not assign to the Result variable which means it is undefined.
procedure TForm1.Button1Click(Sender: TObject);
var
xlap,xlbook,xlsheet:variant;
y:integer;
begin
xlap:=createoleobject('excel.application');
xlbook:=xlap.workbooks.add;
xlap.visible:=true;
xlsheet:=xlbook.worksheets.add;
for y:=1 to 50 do
begin
xlsheet.cells[y,2].value:= concat('=IF(A',y,'>6,"Good","Bad")')
inc(y);
end;
end;
That's my code to make an Excel through Delphi. I want to input the IF formula into column B of the Excel, but there is error when I use the concat('=IF(A',y,'>6,"Good","Bad")').
May be I need another way to include y between those strings.
Any suggestion? Thanks before
Delphi has a format statement bit like sprintf printf in c, well nearly
xlsheet.cells[y,2].value:= format('=IF(A%d>6,"Good", "Bad")',[y])
%d is a place holder for an int. Look it up for loads of other stuff.
NB the variables you want to interpolate are assed in an array.
In addition to Tony's answer about Format, here are a couple of other approaches. (Format is great if you have mixed types or many values, but it carries some overhead that might not be needed.)
You can concatenate strings with a simple + - in fact, the Concat documentation says it does the same thing but is faster:
Temp := 'ing';
Str := 'Test' + Temp; // Str = 'Testing'
As your y variable is an integer, you'll need to convert it to a string first (note you don't need to Inc(y);, as the loop will do that already - it's automatically incremented from the starting value to the ending value on each pass through the loop):
for y:=1 to 50 do
begin
xlsheet.cells[y,2].value:= '=IF(A' + IntToStr(y) + '>6,"Good","Bad")';
end;
I want to have a text file with a list of strings (say for example comma separated with key and values that I can use for auto replacement) and store each key-value pair in a TDictionary<string, string>. How do I populate the dictionary?
From your comment it seems you want to know how to pull out some key value pairs, comma separated, into a dictionary. Here's a basic example:
procedure PopulateKeyValueDict(Strings: TStrings;
Dict: TDictionary<string, string>);
var
CommaPos: Integer;
Line: string;
Key, Value: string;
begin
for Line in Strings do
begin
CommaPos := Pos(',', Line);
if CommaPos=0 then
raise Exception.CreateFmt(
'Could find comma separated key/value pair in ''%s''',
[Line]
);
Key := Copy(Line, 1, CommaPos-1);
Value := Copy(Line, CommaPos+1, MaxInt);
Dict.Add(Key, Value);
end;
end;
You may likely want to add more error-checking and so on, but I'm assuming you already know how to do that. This example illustrates splitting a line on the first comma, and also how to populate a dictionary.
In order to use it you need to transfer your file to a TStrings object. That's routine:
var
Strings: TStringList;
....
Strings := TStringList.Create;
try
Strings.LoadFromFile(FileName);
PopulateKeyValueDict(Strings, Dict);
finally
Strings.Free;
end;
If you only have one-to-one key-value relation (not like three key words "apple" and "apples" and "McIntoshes" would be turned into "McIntosh") - then probably the simpliest way would be to use TStringList, providing that
U make your file exactly of Key=Value lines, not Key,Value
U either need it case sensitive or do UpperCase over the file.
Then u use http://docwiki.embarcadero.com/Libraries/XE3/en/System.Classes.TStrings.Values
To speed things up a bit you can use THashedStringList of IniFiles unit.
There also was somethign similar in JCL in JclXML unit.
I'm doing some work with code generation, and one of the things I need to do is create a function call where one of the parameters is a function call, like so:
result := Func1(x, y, Func2(a, b, c));
TStringList.CommaText is very useful for generating the parameter lists, but when I traverse the tree to build the outer function call, what I end up with looks like this:
result := Func1(x, y, "Func2(a, b, c)");
It's quoting the third argument because it contains commas, and that produced invalid code. But I can't do something simplistic like StringReplace all double quotes with empty strings, because it's quite possible that a function argument could be a string with double quotes inside. Is there any way to make it just not escape the lines that contain commas?
You could set QuoteChar to be a space, and you'd merely get some extra spaces in the output, which is generally OK since generated code isn't usually expected to look pretty. String literals would be affected, though; they would have extra spaces inserted, changing the value of the string.
Free Pascal's TStrings class uses StrictDelimiter to control whether quoting occurs when reading the DelimitedText property. When it's true, quoting does not occur at all. Perhaps Delphi treats that property the same way.
Build an array of "unlikely characters" : non-keyable like †, ‡ or even non-printable like #129, #141, #143, #144.
Verify you don't have the 1st unlikely anywhere in your StringList.CommaText. Or move to the next unlikely until you get one not used in your StringList.CommaText. (Assert that you find one)
Use this unlikely char as the QuoteChar for your StringList
Get StringList.DelimitedText. You'll get the QuoteChar around the function parameters like: result := Func1(x, y, †Func2(a, b, c)†);
Replace the unlikely QuoteChar (here †) by empty strings...
What about using the Unicode version of AnsiExtractQuotedStr to remove the quotes?
Write your own method to export the contents of your TStringList to a string.
function MyStringListToString(const AStrings: TStrings): string;
var
i: Integer;
begin
Result := '';
if AStrings.Count = 0 then
Exit;
Result := AStrings[0];
for i := 1 to AStrings.Count - 1 do
Result := Result + ',' + AStrings[i];
end;
Too obvious? :-)
Alternatively, what would happen if you set StringList.QuoteChar to #0 and then called StringList.DelimitedText?
We have written a descendant class of TStringList in which reimplemented the DelimitedText property. You can copy most of the code from the original implementation.
var
LList: TStringList;
s, LOutput: string;
begin
LList := TStringList.Create;
try
LList.Add('x');
LList.Add('y');
LList.Add('Func2(a, b, c)');
for s in LList do
LOutput := LOutput + s + ', ';
SetLength(LOutput, Length(LOutput) - 2);
m1.AddLine('result := Func1(' + LOutput + ')');
finally
LList.Free;
end;
end;
Had the same problem, here's how I fixed it:
s := Trim(StringList.Text)
that's all ;-)