The time-dependent changes in concentration are represented by a logarithmic graph with errors. What follows is the original code by Dr. Berendsen.

1. from plotsvg import *
2. time = [20., 40., 60., 80., 100., 120., 140., 160., 180.]
3. conc = [75., 43., 26., 16., 10., 5., 3.5, 1.8, 1.6]
4. err = [4., 3., 3., 3., 2., 2., 1., 1., 1.]
5. f = Figure()
6. f.frame([0,200],[1,100],xlabel='time <i> t</i>/s', ylabel='concentration <i>c</i>mmol L< sup >-1</sup>', yscale='log')
7. f.plotp([time,conc],ybars=err)
8. f.show()

In many laboratories it is likely that data are changed but programs remain unchanged. Thus the revised code2.5.py reads csv files (contents). The first line of the csv file is a headling, comprising 3 items corresponding to i, x, y. If an item begins with a letter i, the data of that column are understood as integers.

readData(file_name,check) of hwbfiles.py is invoked to read file. Part of the test program is shown below.

1. import hwbfiles as hf
2. f = fileRead('tab2.5.csv', False)
3. print(f.fname + ' has ' + str(f.ndata) + ' data')
4. print('item size =',f.nitem)
5. print('x=',f.xa)