Steven D'Aprano wrote:
On Mon, 08 Jun 2009 18:13:50 +0200, Francesco Pietra wrote:
I come 'naked', which is unusual and unfair.
???
However, I find it
difficult to give a correct start. The files consist, among other
things, of a huge number of blocks of the type
NSTEP = 1000 TIME(PS) = 152.000 TEMP(K) = 298.54 PRESS =
89.4 Etot = -134965.2123 EKtot = 41282.1781 EPtot =
-176247.3905 BOND = 1771.7644 ANGLE = 6893.3003 DIHED
= 4660.1650 1-4 NB = 1931.6071 1-4 EEL = 7799.8343
VDWAALS = 19047.1551 EELEC = -218354.9960 EHBOND =
0.0000 RESTRAINT = 3.7793 EAMBER (non-restraint) =
-176251.1698 EKCMT = 16048.2253 VIRIAL = 14755.8154 VOLUME
= 669299.5681
Density =
0.9896
Ewald error estimate: 0.8252E-05
(in attachment what surely is a correct reproduction of columns)
I would like to extract values corresponding to variable DIHED (here
4660.1650) and getting also the mean value from all DIHED.
Thanks for giving a possible attack
Assuming no DIHED value will ever be split over two lines:
data = open(filename)
values = []
for line in data:
if line and line.strip(): # ignore blanks
words = line.strip().split()
try:
i = words.index("DIHED")
except IndexError:
continue
values.append(float(words[i+2]))
mean = sum(values)/len(values)
should do the job.
str.index raises ValueError, not IndexError. Anyway, your code could be
shortened slightly:
data = open(filename)
values = []
for line in data:
words = line.split()
try:
i = words.index("DIHED")
values.append(float(words[i + 2]))
except ValueError:
pass
mean = sum(values) / len(values)
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