What do you want to achieve? $header_present = ''; will set $header_present to an empty string. $header_present = undef; will set $header_present to undef which is the uninitialised state. The one you need depends on code you've not shown us.

True laziness is hard work

In reply to Re^3: Array condition always true by GrandFather
in thread Array condition always true by Anonymous Monk

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