1.1  9   5.2
1.762543E-02
0 0.01 0.001

9 3 7

F = open(filename, 'r')
n = F.read().split()

open F, $filename; 
$s = join "", <F>; 
@n = split ' ', $s;

(-3, 1.4)  or  (-1.437625E-9, 7.11)  or  (  4, 2 )

m = re.search(r'\(\s*([^,]+)\s*,\s*([^,]+)\s*\)', 
              '(-3,1.4)')
re, im = [float(x) for x in m.groups()]

$s="(-3, 1.4)"; 
($re,$im)= $s=~ /\(\s*([^,]+)\s*,\s*([^,]+)\s*\)/;

\(\s*([^,]+)\s*,\s*([^,]+)\s*\)

s = '(-3,  1.4 )'
re, im = s[1:-1].split(',')

def debug(leading_text, variable):
    if os.environ.get('MYDEBUG', '0') == '1':
        print leading_text, variable

template <class T>
void debug(std::ostream& o, 
           const std::string& leading_text, 
           const T& variable)
{ 
  char* c = getenv("MYDEBUG");
  bool defined = false;
  if (c != NULL) {  // if MYDEBUG is defined ...
    if (std::string(c) == "1") {  // if MYDEBUG is true ...
      defined = true;
    }
  }
  if (defined) {
    o <<  leading_text << " " << variable << std::endl; 
  }
}

# f is some data
plot(f)

plot(f, label='f', xrange=[0,10])

plot(f, label='f', xrange=[0,10], title='f demo',
     linetype='dashed', linecolor='red')

def plot(data, label='', xrange=None, title='',
         linetype='solid', linecolor='black', ...)

if xrange is not None:  # i.e. xrange is specified by the user
    if isinstance(xrange, list):      # list [xmin,xmax] ?
        xmin = xrange[0];  xmax = xrange[1]
    elif isinstance(xrange, str):     # string 'xmin:xmax' ?
        xmin, xmax = re.search(r'(.*):(.*)',xrange).groups()
    elif isinstance(xrange, float):   # just a float?
        xmin = 0;  xmax = xrange

c = 1            # c is an integer
c = [1,2,3]      # c is a list

double c; c = 5.2;   # c can only hold doubles
c = "a string..."    # compiler error

$b = '1.2'
$c = 5*$b;   # implicit type conversion: '1.2' -> 1.2

b = '1.2'
c = 5*b      # illegal; no implicit type conversion

a = 1.2
no of iterations = 100
solution strategy = 'implicit'
c1 = 0
c2 = 0.1
A = 4
c3 = StringFunction('A*sin(x)')

file = open('inputfile.dat', 'r')
for line in file:
    # first replace blanks on the left-hand side of = by _
    variable, value = line.split('=').strip()
    variable = re.sub(' ', '_', variable)
    exec(variable + '=' + value)   # magic...

set heat conduction = 5.0
set dt = 0.1
set rootfinder = bisection
set source = V*exp(-q*t) is function of (t) with V=0.1, q=1
set bc = sin(x)*sin(y)*exp(-0.1*t) is function of (x,y,t)

#!/usr/bin/env python
from Tkinter import *
root = Tk()
Label(root, text='Hello, World!',
      foreground="white", background="black").pack()
root.mainloop()

for i in range(len(A)):
    A[i] = ...

http://folk.uio.no/hpl/scripting/softwarelist.html

http://folk.uio.no/hpl/scripting/TCSE3-3rd-examples.tar.gz

tar xvzf TCSE3-3rd-examples.tar.gz
export scripting=`pwd`

$scripting/src/py/intro/hw.py

python hw.py 3.4

./hw.py 3.4

Hello, World! sin(3.4)=-0.255541102027

#!/usr/bin/env python

# load system and math module:
import sys, math       

# extract the 1st command-line argument:
r = float(sys.argv[1]) 

s = math.sin(r)

print "Hello, World! sin(" + str(r) + ")=" + str(s)

chmod a+rx hw.py

python hw.py 1.4   # first line is not treated as comment
./hw.py 1.4        # first line is used to specify an interpreter

import sys, math  

r = sys.argv[1]         # r is string
s = math.sin(float(r))  

# sin expects number, not string r
# s becomes a floating-point number

Hello, World! sin(3.4)=-0.255541102027

print "Hello, World! sin(" + str(r) + ")=" + str(s)

print "Hello, World! sin(%g)=%g" % (r,s)

print "Hello, World! sin(%(r)g)=%(s)g" % vars()

s1 = "some string with a number %g" % r
s2 = 'some string with a number %g' % r  # = s1

text = """
large portions of a text
can be conveniently placed
inside triple-quoted strings
(newlines are preserved)"""

s3 = r'\(\s+\.\d+\)'
# with ordinary string (must quote backslash):
s3 = '\\(\\s+\\.\\d+\\)'

./datatrans1.py infilename outfilename

infilename  = sys.argv[1]
outfilename = sys.argv[2]

try:
    infilename  = sys.argv[1]
    outfilename = sys.argv[2]
except:
    # try block failed,
    # we miss two command-line arguments
    print 'Usage:', sys.argv[0], 'infile outfile'
    sys.exit(1)

ifile = open( infilename, 'r')  # r for reading
ofile = open(outfilename, 'w')  # w for writing

afile = open(appfilename, 'a')  # a for appending

for line in ifile:
    # process line

0.1   1.4397
0.2   4.325
0.5   9.0

for line in ifile:
    pair = line.split()
    x = float(pair[0]); y = float(pair[1])
    fy = myfunc(y)  # transform y value
    ofile.write('%g  %12.5e\n' % (x,fy))

while 1:
    line = ifile.readline()  # read a line
    if not line: break
    # process line

lines = ifile.readlines()

# go through each line, 
# split line into x and y columns

x = []; y = []   # store data pairs in lists x and y

for line in lines:
    xval, yval = line.split()
    x.append(float(xval))
    y.append(float(yval))

for i in range(start,stop,inc):
    ...
for j in range(stop):
    ...

i = start, start+inc, start+2*inc, ..., stop-1
j = 0, 1, 2, ..., stop-1

ofile = open(outfilename, 'w') # open for writing

for i in range(len(x)):
    fy = myfunc(y[i])  # transform y value
    ofile.write('%g  %12.5e\n' % (x[i], fy))

ofile.close()

./datatrans1.py infile outfile

# or
datatrans1.py infile outfile

python datatrans1.py infile outfile

#!/usr/local/bin/python

#!/home/hpl/projects/scripting/Linux/bin/python

#!/usr/bin/env python

./datatrans1.py qqq someoutfile
Traceback (most recent call last):
  File "./datatrans1.py", line 12, in ?
    ifile = open( infilename, 'r')
IOError:[Errno 2] No such file or directory:'qqq'

from py4cs.numpytools import *
x = sequence(0, 1, 0.001)  # 0.0, 0.001, 0.002, ..., 1.0
x = sin(x)                 # computes sin(x[0]), sin(x[1]) etc.

for i in range(len(x)):
    x[i] = sin(x[i])

import py4cs.filetable
f = open(infilename, 'r')
x, y = py4cs.filetable.read_columns(f)
f.close()

from py4cs.numpytools import *  # import everything in NumPy
x = 10*x
y = 2*y + 0.1*sin(x)

f = open(outfilename, 'w')
py4cs.filetable.write_columns(f, x, y)
f.close()

x = zeros(n, Float)  # array with indices 0,1,...,n-1
x = zeros((m,n), Float)    # two-dimensional array
x[i,j] = 1.0               # indexing
x = zeros((p,q,r), Float)  # three-dimensional array
x[i,j,k] = -2.1
x = sin(x)*cos(x)

from py4cs.anyplot.gnuplot_ import *
x = sequence(0, 2, 0.1)
y = x + sin(10*x)
plot(x, y)

Unix/DOS> ipython
...
In [1]:3*4-1
Out[1]:11

In [2]:from math import *

In [3]:x = 1.2

In [4]:y = sin(x)

In [5]:x
Out[5]:1.2

In [6]:y
Out[6]:0.93203908596722629

In [6]:y
Out[6]:0.93203908596722629

In [7]:_ + 1
Out[7]:1.93203908596722629

In [1]: import math

In [2]: math.<TABKEY>
math.__class__         math.__str__           math.frexp
math.__delattr__       math.acos              math.hypot
math.__dict__          math.asin              math.ldexp
...

In [2]: my_variable_with_a_very_long_name = True

In [3]: my<TABKEY>
In [3]: my_variable_with_a_very_long_name

In [1]:run scriptfile arg1 arg2 ...

In [1]:run datatrans2.py .datatrans_infile tmp1

In [29]:%pdb on  # invoke pdb automatically
In [30]:run datatrans2.py infile tmp2

/home/work/scripting/src/py/intro/datatrans2.py
      7     print "Usage:",sys.argv[0], "infile outfile"; sys.exit(1)
      8
----> 9 ifile = open(infilename, 'r')  # open file for reading
     10 lines = ifile.readlines()      # read file into list of lines
     11 ifile.close()

IOError: [Errno 2] No such file or directory: 'infile'
> /home/work/scripting/src/py/intro/datatrans2.py(9)?()
-> ifile = open(infilename, 'r')  # open file for reading
(Pdb) print infilename
infile

 
somescript -option1 value1 -option2 value2

oscillator < file

3.0
0.04
1.0
...
(i.e., values of m, b, c, etc.)

set title 'case: m=3 b=0.7 c=1 f(y)=y A=5 ...';

# screen plot: (x,y) data are in the file sim.dat
plot 'sim.dat' title 'y(t)' with lines;

# hardcopies:
set size ratio 0.3 1.5, 1.0;  
set term postscript eps mono dashed 'Times-Roman' 28;
set output 'case.ps';
plot 'sim.dat' title 'y(t)' with lines;

# make a plot in PNG format as well:
set term png small;
set output 'case.png';
plot 'sim.dat' title 'y(t)' with lines;

oscillator < inputfile

gnuplot -persist -geometry 800x200 case.gp

./simviz1.py -m 3.2 -b 0.9 -dt 0.01 -case run1

m = 1.0; b = 0.7; c = 5.0; func = 'y'; A = 5.0; 
w = 2*math.pi; y0 = 0.2; tstop = 30.0; dt = 0.05; 
case = 'tmp1'; screenplot = 1

# read variables from the command line, one by one:
while len(sys.argv) >= 2:
    option = sys.argv[1];       del sys.argv[1]
    if   option == '-m':
        m = float(sys.argv[1]); del sys.argv[1]
    ...

dir = case              # subdirectory name
import os, shutil
if os.path.isdir(dir):  # does dir exist?
    shutil.rmtree(dir)  # yes, remove old files
os.mkdir(dir)           # make dir directory
os.chdir(dir)           # move to dir

os.system(command)

# examples:
os.system('myprog < input_file')
os.system('ls *')  # bad, Unix-specific

cmd = 'oscillator < %s.i' % case  # command to run
import commands
failure, output = commands.getstatusoutput(cmd)
if failure:
    print 'running the oscillator code failed'
    print output
    sys.exit(1)

f = open(case + '.gnuplot', 'w')
f.write("""
set title '%s: m=%g b=%g c=%g f(y)=%s A=%g ...';
...
""" % (case,m,b,c,func,A,w,y0,dt,case,case))
...
f.close()

cmd = 'gnuplot -geometry 800x200 -persist ' \
      + case + '.gnuplot'
failure, output = commands.getstatusoutput(cmd)
if failure:
    print 'running gnuplot failed'; print output; sys.exit(1)

f = open(case + '.m', 'w')  # write to Matlab M-file
# (the character % must be written as %% in printf-like strings)
f.write("""
load sim.dat              %% read sim.dat into sim matrix
plot(sim(:,1),sim(:,2))   %% plot 1st column as x, 2nd as y
legend('y(t)')
title('%s: m=%g b=%g c=%g f(y)=%s A=%g w=%g y0=%g dt=%g')
outfile = '%s.ps';  print('-dps',  outfile)  %% ps BW plot
outfile = '%s.png'; print('-dpng', outfile)  %% png color plot
""" % (case,m,b,c,func,A,w,y0,dt,case,case))
if screenplot: f.write('pause(30)\n')
f.write('exit\n'); f.close()

if screenplot:
    cmd = 'matlab -nodesktop -r ' + case + ' > /dev/null &'
else:
    cmd = 'matlab -nodisplay -nojvm -r ' + case
failure, output = commands.getstatusoutput(cmd)

./loop4simviz1.py m_min m_max dm \
                  [options as for simviz1.py]

try:
    m_min = float(sys.argv[1])
    m_max = float(sys.argv[2])
    dm    = float(sys.argv[3])
except:
    print 'Usage:',sys.argv[0],\
    'm_min m_max m_increment [ simviz1.py options ]'
    sys.exit(1)

['-b','5','-c','1.1'] -> '-b 5 -c 1.1'

simviz1_options = ' '.join(sys.argv[4:])

./loop4simviz1.py 0.5 2 0.5 -b 2.1 -A  3.6

m_min:  0.5
m_max:  2.0
dm:     0.5
simviz1_options = '-b 2.1 -A 3.6'

for m in range(m_min, m_max, dm):

m = m_min
while m <= m_max:
    case = 'tmp_m_%g' % m
    s = 'python simviz1.py %s -m %g -case %s' % \
        (simviz1_options,m,case)
    failure, output = commands.getstatusoutput(s)
    m += dm

html = open('tmp_mruns.html', 'w')
html.write('<HTML><BODY BGCOLOR="white">\n')

m = m_min
while m <= m_max:
    case = 'tmp_m_%g' % m
    cmd = 'python simviz1.py %s -m %g -case %s' % \
          (simviz1_options, m, case)
    failure, output = commands.getstatusoutput(cmd)
    html.write('<H1>m=%g</H1> <IMG SRC="%s">\n' \
         % (m,os.path.join(case,case+'.png')))
    m += dm
html.write('</BODY></HTML>\n')

# concatenate file1.ps, file2.ps, and so on to 
# one single file figs.ps, having pages with 
# 3 rows with 2 plots in each row (-par preserves 
# the aspect ratio of the plots)

epsmerge -o figs.ps -x 2 -y 3 -par \
         file1.ps file2.ps file3.ps ...

convert -delay 50 -loop 1000 -crop 0x0 \
        plot1.png plot2.png plot3.png plot4.png ...  movie.gif

animate movie.gif  # or display movie.gif

# easy:
'-m %g' % m
# is replaced with
'-%s %s' % (str(prm_name), str(prm_value))
# prm_value plays the role of the m variable
# prm_name ('m', 'b', 'c', ...) is read as input

simviz1.py  : run simulation and visualization
simviz2.py  : additional option for yaxis scale

loop4simviz1.py : m loop calling simviz1.py
loop4simviz2.py : loop over any parameter in
                  simviz2.py and make movie

./loop4simviz2.py m 0.1 6.1 0.5 -yaxis -0.5 0.5 -noscreenplot

./loop4simviz2.py c 5 30 2 -yaxis -0.7 0.7 -b 0.5 \
                  -func siny -noscreenplot

./loop4simviz2.py b 0 2 0.25 -yaxis -0.5 0.5 -A 4

tmp_c.gif          # animated GIF (movie)
animate tmp_c.gif

tmp_c_runs.html    # browsable HTML document
tmp_c_runs.ps      # all plots in a ps-file

tmp_m_2.1   tmp_b_0   tmp_c_29

./loop4simviz2_2html.py m 0.1 6.1 0.5 -yaxis -0.5 0.5 -noscreenplot
ls -d tmp_*
mozilla tmp_m_summary.html

some comment line
1.5
  measurements  model1 model2
     0.0         0.1    1.0
     0.1         0.1    0.188
     0.2         0.2    0.25

0    0.1
1.5  0.1
3    0.2

infilename = sys.argv[1]
ifile = open(infilename, 'r') # open for reading
line = ifile.readline()

dt = float(ifile.readline())

ynames = ifile.readline().split()

outfiles = []
for name in ynames:
    outfiles.append(open(name + '.dat', 'w'))

t = 0.0    # t value
# read the rest of the file line by line:
while 1:
    line = ifile.readline()
    if not line: break

    yvalues = line.split()

    # skip blank lines:
    if len(yvalues) == 0: continue  

    for i in range(len(outfiles)):
        outfiles[i].write('%12g %12.5e\n' % \
                          (t, float(yvalues[i])))
    t += dt

for file in outfiles:  
    file.close()

prm['damping'] = 0.2             # number

def x3(x): 
    return x*x*x
prm['stiffness'] = x3            # function object

prm['model1'] = [1.2, 1.5, 0.1]  # list object

y = {}           # declare empty dictionary
# ynames: names of y curves
for name in ynames:
    y[name] = [] # for each key, make empty list

lines = ifile.readlines()  # list of all lines
...
for line in lines[3:]:
    yvalues = [float(x) for x in line.split()]
    i = 0  # counter for yvalues
    for name in ynames:
        y[name].append(yvalues[i]); i += 1

yvalues = [float(x) for x in line.split()]

# same as
numbers = line.split()
yvalues = []
for s in numbers:
    yvalues.append(float(s))

some comment line
1.5
  measurements  model1 model2
     0.0         0.1    1.0
     0.1         0.1    0.188
     0.2         0.2    0.25

'measurements': [0.0, 0.1, 0.2], 
'model1':       [0.1, 0.1, 0.2], 
'model2':       [1.0, 0.188, 0.25]

y, dt = load_data('somedatafile.dat')
print y

>>> y
{'tmp-model2': [1.0, 0.188, 0.25], 
'tmp-model1': [0.10000000000000001, 0.10000000000000001, 
               0.20000000000000001], 
'tmp-measurements': [0.0, 0.10000000000000001, 0.20000000000000001]}

for i in range(len(list)):
    e1 = list1[i];  e2 = list2[i]
    # work with e1 and e2

for e1, e2 in zip(list1, list2):
    # work with element e1 from list1 and e2 from list2

for name, value in zip(ynames, yvalues):
    y[name].append(value)

from convert3 import load_data, dump_data

y, timestep = load_data('.convert_infile1')

from math import fabs
for name in y:  # run through keys in y
    maxabsy = max([fabs(yval) for yval in y[name]])
    print 'max abs(y[%s](t)) = %g' % (name, maxabsy)

dump_data(y, timestep)

if __name__ == '__main__':
    import sys
    try:     
        infilename = sys.argv[1]
    except:  
        usage = 'Usage: %s infile' % sys.argv[0]
        print usage; sys.exit(1)
    y, dt = load_data(infilename)
    dump_data(y, dt)

unix> ./convert3.py someinputfile.dat

import convert3
y, dt = convert3.load_data('someinputfile.dat')
# do more with y?
dump_data(y, dt)

s = myjoin(['s1', 's2', 's3'], '*')
# s becomes 's1*s2*s3'

function myjoin(list, delimiter)
  joined = first element in list
  for element in rest of list:
    concatenate joined, delimiter and element
  return joined

"""
unix> python hw.py 3.1459
Hello, World! sin(3.1459)=-0.00430733309102
"""

unix> a2ps --line-numbers=1 -4 -o outputfile.ps *.py

>>> t = 0.1
>>> def f(x):
...     return math.sin(x)
...
>>> f(t)
0.099833416646828155
>>> os.path.splitext('/some/long/path/myfile.dat')
('/some/long/path/myfile', '.dat')

>>> help(os.path.splitext)

# #if defined('DEBUG') and DEBUG >= 2
# write out debug info at level 2:
...
# #elif DEBUG == 0
# write out minimal debug info:
...
# #else
# no debug output
# #endif

#  #include "myfile.py"

# #ifdef MyDEBUG
....debug code....
# #endif

# #define MyDEBUG

# #define MyDEBUG 2

preprocess -DMyDEBUG=2 myscript.p.py > myscript.py

cmd = 'myprog -c file.1 -p -f -q > res'
failure = os.system(cmd)
if failure:
  print '%s: running myprog failed' % sys.argv[0]
  sys.exit(1)

pipe = os.popen(cmd)
output = pipe.readlines()
pipe.close()

for line in output:
  # process line

import commands
failure, output = commands.getstatusoutput(cmd)

if failure:
    print 'Could not run', cmd; sys.exit(1)

for line in output.splitlines()  # or output.split('\n'):
    # process line

gnuplot = os.popen('gnuplot -persist', 'w')
gnuplot.write("""
set xrange [0:10]; set yrange [-2:2]
plot sin(x)
quit
""")
gnuplot.close()  # gnuplot is now run with the written input

gnuplot <<EOF
set xrange [0:10]; set yrange [-2:2]
plot sin(x)
quit
EOF

# copy files to remote host via scp and password dialog
cmd = 'scp %s %s@%s:%s' % (filename, user, host, directory)
import pexpect
child = pexpect.spawn(cmd)
child.expect('password:')
child.sendline('&%$hQxz?+MbH')
child.expect(pexpect.EOF)  # important; wait for end of scp session
child.close()

src/py/examples/simviz/simviz1_ssh_pexpect.py

infilename = '.myprog.cpp'
infile = open(infilename, 'r')  # open file for reading 

# load file into a list of lines:
lines = infile.readlines()    

# load file into a string:
filestr = infile.read()

while 1:
    line = infile.readline()
    if not line: break
    # process line

outfilename = '.myprog2.cpp'
outfile = open(outfilename, 'w')
outfile.write('some string\n')

outfile = open(outfilename, 'a')
outfile.write('....')

b =  1.2       # b is a number
b = '1.2'      # b is a string
a = 0.5 * b    # illegal: b is NOT converted to float
a = 0.5 * float(b)   # this works

==   !=  <  >  <=  >=

b = '1.2'

if b < 100:    print b, '< 100'
else:          print b, '>= 100'

if float(b) < 100:   # floating-point number comparison
# or
if b < str(100):     # string comparison

a = '';  a = [];  a = ();  a = {};  # empty structures
a = 0;   a = 0.0
if a:       # false
if not a:   # true

arglist = [myarg1, 'displacement', "tmp.ps"]

arglist[0] = myarg1
arglist[1] = 'displacement'

n = 100
mylist = [0.0]*n

arglist = []  # start with empty list
arglist.append(myarg1)
arglist.append('displacement')

 filename, plottitle, psfile  = arglist
(filename, plottitle, psfile) = arglist
[filename, plottitle, psfile] = arglist

filename = arglist[0]
plottitle = arglist[1]

for entry in arglist:
    print 'entry is', entry

start = 0;  stop = len(arglist);  step = 1
for index in range(start, stop, step):
    print 'arglist[%d]=%s' % (index,arglist[index])

mylist.reverse()  # reverse order
for item in mylist:
    # do something...