Q: pattern in list of derivatives
- To: mathgroup at smc.vnet.net
- Subject: [mg22696] Q: pattern in list of derivatives
- From: Klaus Duellmann <k.duellmann at uni-mannheim.de>
- Date: Wed, 22 Mar 2000 00:28:03 -0500 (EST)
- Organization: Mannheim University
- Sender: owner-wri-mathgroup at wolfram.com
Dear Mathgroup Member,
I can extract all derivatives from
e.g. s1 = a u'[x] + a u''[x]
by Cases[{s1}, Derivative[_][u][x],-1] and get
{u'[x],u''[x]}
But for mixed derivatives
e.g. {a u[x,y]^(0,1) + c u[x,y]^(1,1)}
the correponding command Cases[{s1}, Derivative[_][u][x,y],-1]
doesn't work and I receive only the empty list {}.
Any help is much appreciated!
Klaus Duellmann
Mannheim University
E-mail: k.duellmann at uni-mannheim.de