The code is using substr as an lvalue. That is, on the left-hand side of the assignent operator '='. What that does, is it replaces the substring denoted by the parameters to substr, by whatever is assigned.

So, in your example, substr( '20050608', 2, 5 ) represents the sub string '..05060.'.

The value being assign is '2005' . '05'

The result is that dots in '20.....8' get replaced with '200506' giving '202005068'.

But then, maybe the question you're asking is "Why is the code doing this?" -- in which case: Sorry, I have no idea, it doesn't seem to make much sense.

Maybe it's a coding error and the intent would be clear from some more context?

Example: It might be an (erronously coded) attempt to convert US-style date formats (month/day/year) to Euro-style (day/month/year), but without context there is no way to tell.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
The "good enough" maybe good enough for the now, and perfection maybe unobtainable, but that should not preclude us from striving for perfection, when time, circumstance or desire allow.

In reply to Re: What is substring working on here. by BrowserUk
in thread What is substring working on here. by Scarborough

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