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Frequently Asked Questions

WReach? Is that connected to WRI somehow?

The "WR" in my name has nothing to do with the company that develops Mathematica. It is just a coincidence.

Why do you start all your global variable names with $?

I use dollar signs for ad hoc global variables because I have been bitten too many times by accidentally assigning an own-value to a symbol that I happen to use, for example, in a symbolic equation. So I am in the habit of writing $x instead of x. I stick to that convention even for longer symbols like $initialUrl. Just like the regular symbol convention, Mathematica's predefined global symbols all start with a capital letter after the $. My ad hoc symbols always start with a lower case letter, so there is no conflict.

Why do you put semicolons and commas at the beginning of the line instead of at the end like a normal person?

I don't think of it that way. Rather, I switch from horizontal to vertical layout when a single expression is too long to fit on one line. This has the interesting side-effect of making the important delimiters stand out and line up. I first ran into this practice in the SQL community. SQL "programs" have the unpleasant property that they must be written as a single statement -- even if that statement is a hundred lines long (or more!). Sometimes Mathematica expressions share that property.


Sep
30
awarded  Good Answer
Sep
30
revised Multiplayer game in Mathematica: how to communicate between kernels?
changed `Hold` to `HoldComplete` in `LinkRead` after advice from JacobAkkerboom
Sep
29
awarded  Nice Answer
Sep
29
comment Is there a comprehensive list of functions with V10 operator forms?
@RunnyKine Good idea. Done.
Sep
29
revised Is there a comprehensive list of functions with V10 operator forms?
added a required Needs statement
Sep
29
revised Bug in Operator Form of StringCases
edited body
Sep
29
revised Bug in Operator Form of StringCases
added the notes about the complexities of currying `StringCases` and `Cases`
Sep
29
answered Bug in Operator Form of StringCases
Sep
29
revised Is there a comprehensive list of functions with V10 operator forms?
added the note about `StringCases`
Sep
29
answered Is there a comprehensive list of functions with V10 operator forms?
Sep
26
answered Change last column of a matrix
Sep
26
comment Why does my dataset lose its typesetting when I add columns?
The impact of type inference upon typesetting is discussed in detail here. There might be enough information there for the present question to be considered a duplicate.
Sep
24
awarded  Autobiographer
Sep
24
comment How to replace the first occurance in an expression instead of replacing all?
+1 With version 10, we can use FirstPosition, e.g. HoldForm[x + 2 + 4 + x] // ReplacePart[#, FirstPosition[#, x] -> 4] &.
Sep
24
awarded  Nice Answer
Sep
22
comment Elementwise operation, part deux
The implementation of generators is explored in this question. But if you are finding Do to be non-performant then you'll really hate the solution proposed there :)
Sep
22
awarded  Enlightened
Sep
21
revised How to use Mathematica for traditional programming
added links
Sep
21
revised How to use Mathematica for traditional programming
added the link to How To Create a Lecture Notebook
Sep
21
answered How to use Mathematica for traditional programming