       Re: Pattern matching in functions

• To: mathgroup at smc.vnet.net
• Subject: [mg54454] Re: [mg54379] Pattern matching in functions
• From: DrBob <drbob at bigfoot.com>
• Date: Sun, 20 Feb 2005 00:11:12 -0500 (EST)
• References: <200502190732.CAA06160@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Something like this?

Cases[l^4*a[b][l] + l*a[c][l], a[x_][y_] -> x, {0, Infinity}]

{b,c}

or

Cases[l^4*a[b][l] + l*a[c][l], a[x_] -> x, {0, Infinity}, Heads -> True]

{b, c}

or

Cases[l^4*a[b][l] + l*a[c][l], a[x_][y_] -> {x, y}, {0, Infinity}]

{{b,l},{c,l}}

Bobby

On Sat, 19 Feb 2005 02:32:49 -0500 (EST), Maximilian Ulbrich <mulbrich at berkeley.edu> wrote:

> Hi,
>
> I would like to find subexpressions using Cases.
> In the following case, I expected to find a[b] and a[c] and therefore
> get {b,c} as the result. However, I get {l,l}.
> What happens and how can I solve this?
>
> Cases[l^4*a[b][l] + l*a[c][l], x_a[y_] -> y, {0, Infinity}]
>
> Thanks,
> Max
>
>
>
>

--
DrBob at bigfoot.com
www.eclecticdreams.net

```

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