BUILT-IN MATHEMATICA SYMBOL
specifies the number of previous lines of input and output to keep in a Mathematica session.
- The default setting for $HistoryLength is Infinity.
- Values of In[n] and Out[n] corresponding to lines before those kept are explicitly cleared.
- Using smaller values of $HistoryLength can save substantial amounts of memory in a Mathematica session.
The default is to save the entire history:
Change the setting to save no history:
This means the previous input can no longer be used directly:
By assigning to a variable you can still refer to previous results:
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