substitution

I have a python function which generates a sympy.Matrix with symbolic entries. It works effectively like: import sympy as sp M = sp.Matrix([[1,0,2],[0,1,2],[1,2,0]]) def make_symbolic_matrix(M): M_sym = sp.zeros(3) syms = ['a0:3'] for i in xrange(3): for j in xrange(3): if M[i,j] == 1: M_sym = syms[i] elif M[i,j] == 2: M_sym = 1 - syms[i] return M_sym This works just fine. I get a matrix out, which I can use for all the symbolical calculations I need. My issue is that now I want to evaluate my matrix at specified parameter-value. Usually I would just use the .subs attribute. However, since the

How can I replace a list with another list that contain the variable to be replaced. for example rep([x, d, e, z, x, z, p], [x=z, z=x, d=c], R). R = [z, c, e, x, z, x, p] the x to z and z doesn't change after it has been replaced. so far I did only the one without the list rep([], _, []). rep(L1, H1=H2, L2) :- rep(L1, H1, H2, L2). rep([],_,_,[]). rep([H|T], X1, X2, [X2|L]) :- H=X1, rep(T,X1,X2,L), !. rep([H|T],X1,X2,[H|L]) :- rep(T,X1,X2,L). I find your code rather confused. For one thing, you have rep/3 and rep/4 , but none of them have a list in the second position where you're passing the

I would like to know when and why should I use {$var} echo "This is a test using {$var}"; and when (and why) should I use the simple form $var echo "This is a test using $var"; You would use the latter when a) not accessing an object or array for the value, and b) no characters follow the variable name that could possibly be interpreted as part of it. http://php.net/manual/en/language.variables.variable.php In order to use variable variables with arrays, you have to resolve an ambiguity problem. That is, if you write $$a[1] then the parser needs to know if you meant to use $a[1] as a variable,

Small example: perl -e '$s="aaabbcc";$c=()=$s=~/a/g;print"$c\n$s\n"' (m//g) outputs 3 aaabbcc whereas perl -e '$s="aaabbcc";$c=()=$s=~s/a/x/g;print"$c\n$s\n"' (s///g) outputs 1 xxxbbcc I'd like to do both things at once without having to match first: substitute and know the number of substitutions. Obviously a s///g does not return the number of substitutions in scalar context--unlike m//g does with matches. Is this possible? If yes, how? perlre, perlvar and perlop provided no help (or I just couldn't find it). s/// does return the number of substitutions made in scalar context. From perlop

I am trying to set up a function to reformat a string that will later be concatenated. An example string would look like this: Standard_H2_W1_Launch_123x456_S_40K_AB Though sometimes the " S " doesn't exist, and sometimes the "40K" is "60K" or not there, and the "_AB" can also be "_CD" or _"EF". Finally, all underscores need to be changed to hyphens. The final product should look like this: Standard-H2-W1-Launch-123x456- I have four functions that if ran one after the other will take care of all of this: =SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(A2,"_AB","_"),"_CD","_"),"_EF","_") =SUBSTITUTE

I have one project where I need to apply a dozen or so regex to about 100 files using python. 4+ hours of searching the web for various combinations including "(merge|concatenate|stack|join|compile) multiple regex in python" and I haven't found any posts regarding my need. This is a mid-sized project for me. There are several smaller regex projects that I need which take only 5-6 regex patterns applied over only a dozen or so files. While these will be a great aid in my work, the grand-daddy project is a applying a file of 100+ search, replace strings to any new file I get. (Spelling

Hy, I have the following code: import java.io.*; import java.util.ArrayList; import java.util.Scanner; import java.util.regex.*; / public class RegexSimple4 { public static void main(String[] args) { try { Scanner myfis = new Scanner(new File("D:\\myfis32.txt")); ArrayList <String> foundaz = new ArrayList<String>(); ArrayList <String> noduplicates = new ArrayList<String>(); while(myfis.hasNext()) { String line = myfis.nextLine(); String delim = " "; String [] words = line.split(delim); for (String s : words) { if (!s.isEmpty() && s != null) { Pattern pi = Pattern.compile("[aA-zZ]*"); Matcher