Function Repository Resource:

SymbolToSubscript (1.1.0) current version: 3.0.0 »

Source Notebook

Convert symbols into subscript forms

Contributed by: E. Chan-López & Jaime Manuel Cabrera

ResourceFunction["SymbolToSubscript"][expr]

gives the representation with subscripts for one or more unprotected symbols expr.

Details

ResourceFunction["SymbolToSubscript"] does not act on numbers, it just returns them.

ResourceFunction["SymbolToSubscript"] does not act on symbols that already have subscripts, it just returns them.

ResourceFunction["SymbolToSubscript"] does not act on protected heads of functions.

SymbolToSubscripts can be used on symbolic matrices, where it separates numbers with commas.

SymbolToSubscripts[expr,"ToStringFormat" ] can be used to get the string format of expressions.

Examples

Basic Examples (2)

Use SymbolToSubscript with an unprotected symbol:

In[1]:=

Out[1]=

Use SymbolToSubscript with a list of unprotected symbols:

In[2]:=

Out[2]=

In[3]:=

Out[3]=

In[4]:=

$ResourceFunction["SymbolToSubscript"][{x\[Alpha][t], x\[Beta][t]}]$

Out[4]=

Scope (9)

Use SymbolToSubscript with a list of functions with protected heads:

In[5]:=

$ResourceFunction["SymbolToSubscript", ResourceVersion->"1.1.0"][{Sin[t], Cos[x], Tan[s], Cot[x1], BesselJ[0, x1[t] + x2[t]], Csch[(x^(m - 2) - x3) (x^(n + 1) + x2)]}]$

Out[5]=

Use SymbolToSubscript with the default form for the i^th constant C[i]:

In[6]:=

Out[6]=

Use SymbolToSubscript with symbolic matrix:

In[7]:=

Out[8]=

Use SymbolToSubscript with tensor of rank 3:

In[9]:=

$MatrixForm@ ResourceFunction["SymbolToSubscript"]@ D[{x1^2 y1 + x1, -y1 x1^3 - 2 x1}, {{x1, y1}, 2}]$

Out[9]=

Use SymbolToSubscript with tensor of rank 4:

In[10]:=

Out[10]=

If the expression contains symbols with a capital C, the format for the other indexed symbols is the same as i^th constant C[i]:

In[11]:=

$MatrixForm@ ResourceFunction["SymbolToSubscript"]@ D[{C1*x1^2 y1 + x1, -B1*y1 x1^3 - 2 C1*x1}, {{x1, y1}, 2}]$

Out[11]=

Use SymbolToSubscript with a nonlinear system of ordinary differential equations:

In[12]:=

$ResourceFunction["SymbolToSubscript", ResourceVersion->"1.1.0"]@{x1'[t] == -x1[t]^2 - x2[t], x2'[t] == 2 x1[t] - x2[t]^3}$

Out[12]=

Use SymbolToSubscript with a system of partial differential equations:

In[13]:=

$ResourceFunction["SymbolToSubscript"]@{\!$ \*SubscriptBox[\(\[PartialD]$, $t$]$u1[t, x]$\) == \!$ \*SubscriptBox[\(\[PartialD]$, $x$]$(\((u2[t, x] - 1)$\ \*SubscriptBox[$\[PartialD]$, $x$]u1[t, x])\)\) + (16 x t - 2 t - 16 (u2[t, x] - 1)) (u1[t, x] - 1) + 10 x E^(-4 x), \!$ \*SubscriptBox[\(\[PartialD]$, $t$]$u2[t, x]$\) == \!$ \*SubscriptBox[\(\[PartialD]$, ${x, 2}$]$u2[t, x]$\) + \!$ \*SubscriptBox[\(\[PartialD]$, $x$]$u1[t, x]$\) + 4 u1[t, x] - 4 + x^2 - 2 t - 10 t E^(-4 x)}$

Out[13]=

Both the base and subscript in the output are symbols and inherit any existing definitions:

In[14]:=

In[15]:=

Out[15]=

Applications (3)

Format a symbolic polynomial:

In[16]:=

$polynomial[var_Symbol, coeff_Symbol, n_Integer?NonNegative] := Total[Array[ Times[ToExpression[ ToString[coeff] <> ToString[FromDigits[{n - ##}]]], var^#] &, n + 1, 0]]$

In[17]:=

Out[17]=

Format a symbolic matrix:

In[18]:=

$Matrix[symbol_Symbol, {row_Integer?Positive, column_Integer?Positive}] := ToExpression[ Array[ToString[symbol] <> ToString[#1] <> ToString[#2] &, {row, column}]]$

In[19]:=

Out[19]=

In[20]:=

Out[20]=

Use SymbolToSubscript and TeXForm:

In[21]:=

Out[21]=

Define a function for making a Vandermonde matrix:

In[22]:=

$VandermondeMatrix[symbol_Symbol, n_Integer?Positive] := Map[ToExpression, Array[(ToString[symbol] <> ToString[#1])^(#2 - 1) &, ConstantArray[n, 2]], {-1}]$

Format a Vandermonde matrix:

In[23]:=

Out[23]=

The SymbolToSubscript command allows TeXForm to be used correctly when we have expressions with subscripts that are written as symbols:

In[24]:=

Out[24]=

In[25]:=

Out[25]=

In[26]:=

Out[26]=

In[27]:=

Out[27]=

In[28]:=

Out[28]=

Properties and Relations (2)

Use SymbolToSubscript with the resource function HurwitzMatrix:

In[29]:=

$polynomial[var_Symbol, coeff_Symbol, n_Integer?NonNegative] := Total[Array[ Times[ToExpression[ ToString[coeff] <> ToString[FromDigits[{n - ##}]]], var^#] &, n + 1, 0]]$

In[30]:=

Out[31]=

In[32]:=

Out[32]=

Use SymbolToSubscript with the resource function SolutionRulesToFunctions:

In[33]:=

$ResourceFunction["SymbolToSubscript"]@ ResourceFunction[ "SolutionRulesToFunctions"][\[Theta][t] -> \[Theta]0 + t \[Omega]0 + (g t^2 Sin[\[Alpha]])/(3 R)]$

Out[33]=

Possible Issues (2)

Before getting the subscript format, SymbolToSubscript separates the expression x1y2 as {“x”,“1y2”}, and then passes each part to input form using ToExpression. Therefore, with the expression x1y2 we get x_y2 instead x_1y2:

In[34]:=