About a month ago I did an online presentation for a summer class taught by Dr. Jaime Banks, who was over in Germany at the time, for the summer session she and Dr. Nick Bowman are involved with, SPICE: Summer Program in Communications Erfurt. It was really great, and the students had some good questions. I put the slides (slightly edited) up in Slideshare, you can find them here. The talk looked at some work in gaming, play, and communities, using different data. Just the slides are not as good as the slides and the audio, but there they are.
Sunday, July 24, 2016
tl;dr: ttk.Progressbar is max 99 by default, not 100, despite the documentation. If you try to overfill it, it won't accept the call that does so.
I was building a front end for a scraper app, and at first I tried Xcode and the Interface Builder (which I first saw over two decades ago on a NeXT machine, it was glorious then and it still is), but I couldn't get it to mesh with my Python code (so much of the online help is out of date). A friend told me I was being an idiot and should try something simpler, and I settled on TKinter, which had me up and running in very little time. (The front end took only two days, but I wasn't committing every waking hour to it, and I had to figure out how to take my linear Python script and conceive of it in the looping GUI manner, which was difficult.)
I wanted a text box field so the scraper could print to it like it does with Python's print statement to the terminal (but I don't want the user to have to deal with the terminal or the console). I ended up using ScrolledText, which you have to import (well as far as I can tell, and it's working, so, once it works, I don't have time to poke at it too much). (NB: with ScrolledText, I needed setgrid=True to make the frames resize nicely, this was VITAL, packing frames in TKinter is an art I do not yet understand, and with the ScrolledText field, you might want state='normal' to print to it, then state='disabled' so the user doesn't type in it [but loses copy capability], you'll want insert(END, new_string) to print at the bottom of your field, but then you also need see(END) so that it scrolls to the bottom -- otherwise it prints on the bottom but the view stays put at the top. Details.)
Then I wanted two progress bars, one to show the user the scrape progress and the second to show the parsing progress. The scraping one I needed to fudge a little, so I tried....
my_window.scrape_progress.step(10) # first init step
my_window.scrape_progress.step(20) # bigger step
As you can see, that's 10 + 20 + 20 + 50 = 100.
The bar would fill 10% (10), then to about 30% (10+20), then to about 50% (10+20+20), then it wouldn't fill anymore.
Eventually out of annoyance when trying alternatives, instead of 50 in the last step I used 49, and it worked.
So no, the max is not 100, it's 99, so the bar values are probably 0-99 for 100 increments, as 0-100 would be 101 increments. I suspect that step(100) won't work, but step(99) should fill it to 100%.
from Tkinter import *
from ttk import * # ttk widgets should overwrite Tkinter ones in the namespace.
import ScrolledText as tkst # Not sure why this is its own library.
# from my window class def, nothing to do with the Progressbar:
def print_to_text_field(self, the_string):
new_string = '\n' + the_string
Monday, July 4, 2016
How to make a color gradient palette in R for iGraph (that was written tersely for search engine results), since despite some online help I still had a really hard time figuring it out. As usual, now that it works, it doesn't seem to hard, but anyways.
(I had forgotten how horrible blogger is at R code with the "gets" syntax, the arrow, the less than with a dash. Google parses it as code, not text, and it just barfs all over the page, so I think I have to use the equal sign [old school R] instead. It is also completely failing at typeface changes from courier back to default. I see why people use WordPress....)
- Set the resolution for the gradient, that is, how many color steps there are/you want.
- Set up the palette object with a start color and an end color. (Don't call it "palette" like I did at first, that is apparently some other object and it will blow up your code but the error message won't help with figuring it out.)
- You'll want a vector of values that will match to colors in the gradient for your observations, for what I'm doing I got the maximum on the variable in one step...
- And then set up the vector in the second step (so, this is a vector of the same length as the number of observations you have, since each value represents the value that matches up against a color in the gradient). (In my code here, it's a ratio, but the point is you have numerical values for your observations [your nodes] that will be matched to colors in the gradient.)
- Create a vector that is your gradient that has the correct color value for each observation. (The examples of this I could find online were very confusing, and that's why I'm making this post.)
- Draw! (Or you could assign colors to your graph object and then draw.)
Also note that, I think, the my_palette object is actually a function, but it definitely isn't a "palette" in the sense of a selection (or vector) of colors or color values. I think that is part of what makes line 4, below, unusual. Maybe I should have used my_palette_f to be more clear, but if you've made it this far, I have faith in you. (Also note that colorRampPalette is part of R, not part of iGraph.)
- Set resolution, I'm using 100: my_resolution = 100
- Set palette end points, this starts with low values at blue and high values at red: my_palette = colorRampPalette(c('blue','red'))
- Get the max from your variable you want colorized to make the ratio: my_max = max(V(g)$my_var_of_interest, na.rm=TRUE)
- Create your vector of values which will determine the color values for each node. For me it was a ratio, so based on the max value: my_vector = V(g)$my_var_of_interest / my_max
- Notice here we have iGraph's V(g)$var syntax.
- Ok let's explain that. Take my_vector, and bin it into a number of parts -- how many? That's set by the resolution variable (my_resolution). By "bin" I mean cut it up, divide it up, separate it into my_resolution number of elements. So if I have 200 items, I am still going to have 100 colors because I want to see where on the spectrum they all fall. Take that vector as.numeric (since maybe it comes back as factors, I don't know, I didn't poke at that.) Send that resulting vector of numeric elements (which are determined by my_var_of_interest and my_resolution) to the my_palette function along with my_resolution, which returns a vector of hex color values which are the colors you want in the correct order.
- Note that we aren't modifying the colors in the iGraph object, we're just assigning them at run time for plot(). We could assign them to the iGraph object and them draw the graph instead.
my_resolution = 100
my_palette = colorRampPalette(c('blue','red'))
# This gives you the colors you want for every point.
my_max = max(V(g)$my_var_of_interest, na.rm=TRUE)
my_vector = V(g)$my_var_of_interest / my_max
my_colors = my_palette(my_resolution)[as.numeric(cut(my_vector, breaks=my_resolution))]
# Now you just need to plot it with those colors.
Sunday, July 3, 2016
When Gephi, which is great, decides to not exactly work, you can save your Gephi graph file in graphml format and then import it into R (or Python or C/C++) using iGraph so you can also draw it the way you were hoping to. (I'm having an issue with setting the colors at all in Gephi.)
It took me a few tries to figure out which format would work. I need location (since Gephi is good at that but I don't know how to make iGraph or R's SNA package do that) and attributes for the data. So far, so good!
Some helpful pages:
- An iGraph tutorial.
- Another iGraph tutorial.
- iGraph docs for R.
- Gephi file formats.
- iGraph read_graph().
Note!!!! Apparently if you make a variable in R (at least while trying to graph something with plot) and you use a variable for your palette that you name palette, you will destroy (ok ok overwrite) some other official variable or setting also named palette, but the error you get will not at all clue you in to what happened. Better to call your variable my_palette or the_palette, which is what I usually do (so why didn't I do it here?).
Saturday, June 18, 2016
Wednesday, June 15, 2016
Had a great and busy time at ICA 2016: one paper, one panel presentation, moderated a session, and won an award! (Google is being impossible with photos and tables as usual. So much for interfaces.)
I was lucky enough to be invited to speak on the new Computational Methods panel, for the CM interest group. I tried to give the crowd an exhortation to engaging with such methods, because we as social scientists have a lot to offer computational analyses. You can see the slides in SlideShare, but I don't spell it all out in the slides when I present. My presentation got a nice tweet too!
|Presenting on the Computational Methods panel.|
|As part of the Games Division pre-conference in Tokyo at Nihon University (I love the neighborhood there, the Ekoda stop on the Seibu-Ikebukuro line), we all went to Akihabara, and of course we saw and did cool things, like engage in deep discourse with Mario, the working-class Italian-Japanese plumber.
|"You don't think quantitative and qualitative methods|
are complementary? Explain!"
|I also was lucky enough to run into Sanrio's Gudetama in Hong Kong and then again in Japan.|