In many symbolic math systems, such as Matlab or Mathematica, you can use a variable like Ans
or %
to retrieve the last computed value. Is there a similar facility in the Python shell?
-
Underscore.
>>> 5+5 10 >>> _ 10 >>> _ + 5 15 >>> _ 15
John Fouhy : It only works in the interactive shell, though. Don't rely on it for scripts.bk1e : Cool, that works in Ruby's `irb` shell as well.crystalattice : I never knew this but wondered about it for some time. Thanks.From Mark Cidade -
Just for the record, ipython takes this one step further and you can access every result with _ and its numeric value
In [1]: 10 Out[1]: 10 In [2]: 32 Out[2]: 32 In [3]: _ Out[3]: 32 In [4]: _1 Out[4]: 10 In [5]: _2 Out[5]: 32 In [6]: _1 + _2 Out[6]: 42 In [7]: _6 Out[7]: 42
And it is possible to edit ranges of lines with the %ed macro too:
In [1]: def foo(): ...: print "bar" ...: ...: In [2]: foo() bar In [3]: %ed 1-2
Edward Z. Yang : Nice! I'll be sure to keep that in mind if I ever get annoyed at Python's shell (which is, admittedly, a long way off, since I'm used to PHP's tardtastic interactive mode).From Peter Hoffmann
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