有多种方法可以解决此问题。以下是三种解决方案。
解决方案 1
您可以简单地遍历源字符串，检查每个字符是否是需要删除的字符之一。
//Simple function that loops through all characters of the source strings removing them one by one
//It is manipulating the same string all the time
function Removechars1(sourceString: string; sCharsToBeRemoved: string):string;
var I: Integer;
begin
//Assign value of the source string to the result so we can work with result strin from now on
result := SourceString;
//Loop throught the whole result sring starting at end searching for characters to be removed
//We start at the end because when we will be removing characters from the string its length
//will be decreasing.
for I := Length(result) downto 1 do
begin
//Use Pos function to see if specific character in the result string can also be found
//in the sCharsToBeRemoved and therefore needs to be removed
if Pos(result[i], sCharsToBeRemoved) <> 0 then
begin
//If so we delete the specific character
Delete(result,I,1);
end;
end;
end;
解决方案 2
第二种解决方案与第一种类似，但它依赖于在结果中添加不可移动字符。它比第一种解决方案稍慢
//Slightly faster function that also loops through the whole sourceString character by character
//and adds such characters to result string if they are not present in sCharsToBeRemoved string
function RemoveChars2(sourceString: string; sCharsToBeRemoved: string):string;
var I: Integer;
begin
//Prepare enpty string for our result strung to which we will be copying our end characters
result := '';
//Loop through the whole string
for I := 1 to Length(sourceString) do
begin
//If specific haracter can't be found in sCharsToBeRemoved copy that character to the
//result string
if Pos(sourceString[I], sCharsToBeRemoved) = 0 then
begin
result := result + sourceString[I];
end;
end;
end;
解决方案 3
第三种解决方案依赖于字符串助手来替换特定字符。这个是迄今为止最快的三个，需要的时间大约是第一个解决方案处理相同作业所需时间的一半
//Another approach of removing characters from source string that relies on Replace string helper
function RemoveChars3(sourceString: string; sCharsToBeRemoved: string):string;
var I: Integer;
begin
//Assign value of the source string to the result so we can work with result strin from now on
result := sourceString;
//Loop through the sCharsToBeRemoved string so we can then call Replace string helper in order
//to replace all occurrences of such character in sourceString;
for I := 1 to Length(sCharsToBeRemoved) do
begin
result := result.Replace(sCharsToBeRemoved[I],'');
end;
end;
这种方法的主要优点是速度非常快，并且可以轻松修改为能够删除整个子字符串而不仅仅是单个字符。
PS：在我的测试中，您的解决方案实际上是最慢的，比我的第一个解决方案需要多 20% 的时间
TestTring
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CharsToBeRemoved
asjk
Solution 1
1230 ms
Solution 2
1263 ms
Solution 3
534 ms
Your solution
1574 ms