Silly PHP, Trix are for Python

I just discovered that when calling a PHP function, you can't specify functions by parameter name. This is really annoying when you're calling a function with several default parameters and you just want to change the last one. Since you can't just specify the one you want to change by name, you need to include all the other default parameters in order and just change the one parameter you care about.

Case in point, if you want to call htmlentities with $double_encode set to false and the other default parameters unchanged, you have to write

htmlentities("myhtmlcode", ENT_COMPAT, "ISO-8859-1", false).

This is phenomenally absurd. Makes me miss Python... :(

--Arkajit

Python Silliness

So I was implementing the K-Means and the Fuzzy C-Means algorithms in Python for a class assignment and something just wasn't working. I double-checked my logic several times and everything seemed right. And indeed, the logic was right, I just got into trouble using some Python shortcuts.

The * operator in Python is overloaded to allow you do cool things like

a = 'h'*5 # stores 'hhhhh'

So naturally when I needed to initialize a list of lists, I did something like

t = [[]]*3

and expected to get a list with three empty lists. Then here's where I made my error. If you do something like this

t[0].append('hi')

you might think you should get

t = [['hi'], [], []].

That would make sense, but what you actually get is

t = [['hi'], ['hi'], ['hi']]

and that can mess up your logic if you're not careful. What I really wanted was the more verbose

t = [[] for i in range(3)].

In retrospect, it makes sense that the * operator just creates more pointers to the object I'm multiplying, not completely new objects. Thus when I change the underlying object, I change all the copies. But still this wasn't entirely intuitive and is a nasty pitfall to watch out for.

--Arkajit