How can I use a string variable in .bat for-loop?-CodePudding

In a .bat file, it's ok to use a char-type variable in for-loop. The code below, for example,

@echo off
for /l %%p in (15,2,20) do (
    echo %%p
)

gives "15 17 19", as expected. But it doesn't work anymore if I use a string-type variable,

@echo off
for /l %%parameter in (15,2,20) do (
    echo %%parameter
)

I wonder if it's possible to make the 2nd piece of code work. Can somebody help me out? Many thanks.

CodePudding user response：

you can use an ordinary environment variable defined with a for metavariable in place of the for metavariable:

@Echo off

 Set "Loop[1]=%%#"
 Set "Loop[2]=%%@"

 For /l %Loop[1]% in (1 1 5) Do For /l %Loop[2]% in (5 1 9) Do (
  <nul set /p=%Loop[1]%   %Loop[2]%=
  Cmd /c Set /A %Loop[1]%   %Loop[2]%
  Echo(
 )

CodePudding user response：

The use of %value% is used to define variables that contain more than one character. The %% is used to define variables consisting of a single character.

Since only %% is allowed in the for loop, %value% cannot be used to define variables with more than one character. In this case, the only option is to define a single character variable using %%; such as %%p.

The syntax for the for loop is available below:

for %%a in (list) do command [ parameters ]