Question

I’m still learning Python, and I’d love to know a way to make the following work:

a_function(
  for n,item in enumerate(list):
    inside_function(code code code,
                    code code code,
                    code code code))

So there’s a function nested inside another function, and I need to play out the inside function a number of times, but not the outside one. The code I’m working with is not mine so I can’t change the way these functions work.

I can edit with the actual code if anyone needs it, it’s something from PyChart.

Edit: actual code:

ar = area.T(y_coord = category_coord.T(data, 0),
            x_grid_style=line_style.gray50_dash1,
            x_grid_interval=chartlength/5, x_range = (0,chartlength),
            x_axis=axis.X(label="X label"),
            y_axis=axis.Y(label="Y label"))

chart_object.set_defaults(interval_bar_plot.T, direction="horizontal",
                          width=5, cluster_sep = 0, data=data)

ar.add_plot(
  for n,item in enumerate(compactlist):
    interval_bar_plot.T(line_styles = [None, None],
                    fill_styles = [fill_style.red, None],
                    label=compactlist[n], cluster=(n,len(compactlist)))
)

can = canvas.default_canvas()
can.set_title("Chromosome comparison")
can.set_author("Foo")
ar.draw()

The ar.add_plot function creates a working area in the canvas (as I understand it), while the interval_bar_plot function creates the bars, one by one. So I need multiple interval_bar_plot functions but only the one add_plot, or it simply repeats the first bar n times.

Edit: and the error:

  File "intvlbar.py", line 105
    for n,item in enumerate(compactlist):
      ^
SyntaxError: invalid syntax

Answer 1

What you are trying to do is pass several bar plot objects to the add_plot method (documented in here). One way you can do this is to pass them each explicitly. For example:

ar.add_plot(bar1, bar2, bar3)

Examples of this are in the sample code sections of the PyChart documentation for bar plots and interval bar plots, for example.

You do not want to do this because your compactlist might be inconveniently long or of varying length between runs. Another option is to use argument unpacking. Create a list containing your bar plot objects:

bars = [interval_bar_plot.T(line_styles = [None, None],
                            fill_styles = [fill_style.red, None],
                            label=compactlist[n], cluster=(n,len(compactlist)))
        for n,item in enumerate(compactlist)]

Now call add_plot with your bars:

ar.add_plot(*bars)