The last line is simply to show that the final value acquired by f can be accessed outside of the loop as either %f% or !f!, and that %%f is out-of-context and shown as %f.Īnother way to do this without delayedexpansion is for.%%f.do ( This sets the value of f in the required manner (of course, you could always change the name to avoid confusion.) The twist, of course, is that you must use delayedexpansion and the !var! syntax to access the modified value of an environment variable within a block. Metavariables cannot be used in string-manipulation statements like substrings or substitutes, only common environment variables can be used for these operations, hence you need to assign the value of the metavariable f to the environment variable f and then perform the string-substitution task of the environment variable f. This variable can be accessed by using %f% but within a block, it will appear to retain the value it had when the controlling for was parsed (in fact, any %var% is replaced at parse-time by the value of var at that time) The second is the common environment variable f which is established by the set "f=." statement. The first is the loop-control 'metavariable' called f and referenced by %%f.
Your code contains two separate variables called f. Note therefore the use of CALL ECHO %%var%% which displays the changed value of var. Two common ways to overcome this are 1) to use setlocal enabledelayedexpansion and use !var! in place of %var% to access the changed value of var or 2) to call a subroutine to perform further processing using the changed values. Hence, IF (something) else (somethingelse) will be executed using the values of %variables% at the time the IF is encountered. Any %var% within the block will be replaced by that variable's value at the time the block is parsed - before the block is executed - the same thing applies to a FOR.
Within a block statement (a parenthesised series of statements), the entire block is parsed and then executed.
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