Question

我有一个包含文件名列表的变量，根据扩展名，我需要执行不同的操作。我无法在循环中提取扩展名

set BINARIES=file1.dll fil2.dll fil3.sys

:: for each file in list of binaries do
FOR %%G IN (%BINARIES%) DO (
    :: if extension is dll
    if /i [%%G:~-4%]==[.dll] (
        echo dll file
        ) else (
            echo sys file
        )
)

如果条件总是失败。如何正确提取扩展名。

Answer 1

if /i "%%~xG"==".dll"

从cmd shell窗口帮助for /?：

In addition, substitution of FOR variable references has been enhanced.
You can now use the following optional syntax:

    %~I         - expands %I removing any surrounding quotes (")
    %~fI        - expands %I to a fully qualified path name
    %~dI        - expands %I to a drive letter only
    %~pI        - expands %I to a path only
    %~nI        - expands %I to a file name only
    %~xI        - expands %I to a file extension only
    %~sI        - expanded path contains short names only
    %~aI        - expands %I to file attributes of file
    %~tI        - expands %I to date/time of file
    %~zI        - expands %I to size of file
    %~$PATH:I   - searches the directories listed in the PATH
                   environment variable and expands %I to the
                   fully qualified name of the first one found.
                   If the environment variable name is not
                   defined or the file is not found by the
                   search, then this modifier expands to the
                   empty string

The modifiers can be combined to get compound results:

    %~dpI       - expands %I to a drive letter and path only
    %~nxI       - expands %I to a file name and extension only
    %~fsI       - expands %I to a full path name with short names only
    %~dp$PATH:I - searches the directories listed in the PATH
                   environment variable for %I and expands to the
                   drive letter and path of the first one found.
    %~ftzaI     - expands %I to a DIR like output line

Answer 2

我不知道你是否可以使用它：%% G：〜-4％

此外，您必须使用变量的延迟扩展。关键是使用'！'在某些地方而不是'％'。用“set /？”检查，它给出了一个（令人困惑的）例子。

我不记得它背后的理论，但这对我有用：

setlocal enabledelayedexpansion

set BINARIES=file1.dll fil2.dll fil3.sys

:: for each file in list of binaries do
FOR %%G IN (%BINARIES%) DO (
    :: if extension is dll
    set x=%%g
    set y=!x:~-4!
    if /i [%y%]==[.dll] (
        echo dll file
        ) else (
            echo sys file
        )
)

Answer 3

set BINARIES=file1.dll fil2.dll fil3.sys

FOR %%G IN (%BINARIES%) DO echo %%G has a %%~xG extension.

条目列表中的子字符串

3 个答案: