repeatedly performs replacements until expr no longer changes.
- expr//.rules effectively applies /. repeatedly, until the results it gets no longer change.
- It performs one complete pass over the expression using /., then carries out the next pass.
- You should be very careful to avoid infinite loops when you use the //. operator. The command x//.x->x+1 will, for example, lead to an infinite loop.
- ReplaceRepeated takes the option MaxIterations, which specifies the maximum number of times it will try to apply the rules you give. The default setting is MaxIterations->65536. With MaxIterations->Infinity there is no limit.
ReplaceAll does just a single replacement:
ReplaceAll would only remove the outermost head:
Introduced in 1988