# expression.lweight(weight)¶

The left scalar product of an expression by a weight.

## Examples¶

In [1]:
import vcsn
c = vcsn.context('lal_char, q')

In [2]:
e = c.expression('<2>a<3>bc', 'trivial')
e

Out[2]:
$\left\langle 2 \right\rangle \,a \, \left( \left\langle 3 \right\rangle \,b \, c\right)$
In [3]:
e.lweight(c.weight('4'))

Out[3]:
$\left\langle 4 \right\rangle \,\left( \left\langle 2 \right\rangle \,a \, \left( \left\langle 3 \right\rangle \,b \, c\right)\right)$

Instead of e.lweight(w), you may write w * e.

In [4]:
c.weight('4') * e

Out[4]:
$\left\langle 4 \right\rangle \,\left( \left\langle 2 \right\rangle \,a \, \left( \left\langle 3 \right\rangle \,b \, c\right)\right)$

You may even run the simpler:

In [5]:
4 * e

Out[5]:
$\left\langle 4 \right\rangle \,\left( \left\langle 2 \right\rangle \,a \, \left( \left\langle 3 \right\rangle \,b \, c\right)\right)$