字符串简单问题

[omarchen]

一个不定长度的字符串，如何得到从第3个字符到倒数第3个字符中的那传字符
如asdfghjkl要求得到dfghj

[johnzcq]

var str : string ;

begin
str := copy ( 'asdfghjkl' , 3 , ( length( 'asdfghjkl' ) - 4 ) ) ;
end ;


说明：
字符串函数COPY

function Copy(S; Index; Count): string;
function Copy(S; Index; Count): array;

其中:
S : 指明要进行操作的字符串，
INDEX : 指明截取起点，
COUNT : 指明截取长度。

[aniude]

var str_Tmp:String;
begin
str_Tmp:='asdfghjkl';
ShowMessage(Copy(str_Tmp,3,Length(str_Tmp)-4));
end;

[aniude]

感觉DELPHL在字符串方面不爽，除非用正则

[aniude]

Var r2:TRegExpr;
Var s:String;
begin
r2:=TRegExpr.Create;
s:='asdfghjkl';
r2.Expression:='.{2}(.+).{2}';
if r2.Exec(s) Then
ShowMessage(r2.Match[1]);
end;

[jadeluo]

sSou := 'asdfghjkl';
sTar := Copy(sSou, 3, Length(sSou) - 4));

[andyzhou1101]

Copy('asdfghjkl', 3, Length(sSou) - 4);

[andyzhou1101]

错了
想说的是
sSou := 'asdfghjkl';
sTar := Copy(sSou, 3, Length(sSou) - 4));
多了个')'

[diablobaal]

楼上正解
copy函数说明
copy(a,b,c)
将字符串a从第b位开始取，取c个位的子串

[September_1984]

s:= 'asdfghikl'
copy(s,3,length(s)-3);

[飞哥]

总结：

ls同仁一致认为用copy
没错
就是copy

[飞哥]

而且可以配合pos来用

pos 查找子串首次出现的位置
function Pos(Substr: string; S: string): Integer;

Description

In Delphi, Pos searches for a substring, Substr, in a string, S. Substr and S are string-type expressions.

Pos searches for Substr within S and returns an integer value that is the index of the first character of Substr within S. Pos is case-sensitive. If Substr is not found, Pos returns zero.

The PosEx function is similar to Pos, but provides additional features and can be used in C++ code.