A piecewise expression, such as $\left\{\begin{array}{cc}{f}_1& \mathrm{cond1}\\ f_2& \mathrm{cond2}\\ \mathrm{...}& \mathrm{`\; `}\end{array}\right.$, is converted into an ordered list $\left[f_1\,t_1\,f_2\,t_2\,\mathrm{...}\,f_n\,t_n\,f_{n+1}\right]$ which represents the piecewise-defined function:

Here, $t_0=-\mathrm{\infty }$ and $t_{n+1}=\mathrm{\infty }$ are implicit.

The variable x can be stated as an extra argument to the convert function.  If x is not stated then the variable name is deduced if there is exactly one name appearing in the expression.

$f≔\mathrm{piecewise}\left(-1<x\mathbf{and}x\le 0\&comma;x^3\&comma;0<x\mathbf{and}x\le \frac{\mathrm{\pi }}{2}\&comma;\sin \left(x\right)\&comma;\frac{\mathrm{\pi }}{2}<x\&comma;1+\cos \left(x\right)\right)\&colon;$

$\mathrm{convert}\left(f\&comma;\mathrm{pwlist}\&comma;x\right)$

$\left[0\&comma;\mathrm{-1}\&comma;x^3\&comma;0\&comma;\sin \left(x\right)\&comma;\frac{\mathrm{\pi }}{2}\&comma;1+\cos \left(x\right)\right]$

$g≔\mathrm{piecewise}\left(x<1\&comma;a-x\&comma;1\le x\&comma;\ln \left(x\right)\right)\&colon;$

$\mathrm{convert}\left(g\&comma;\mathrm{pwlist}\&comma;x\right)$

$\left[a-x\&comma;1\&comma;\ln \left(x\right)\right]$