1 | initial version |

A possible approach might be the following:

```
vars=[]
f = 0
for counter in range(1,5):
vars.append( var('x'+str(counter) ))
f += mylist[counter] * vars[counter]
```

Then you can use a dictionary to evaluate. Say you have `n`

variables and want variable `i`

in vars to take value `val[i]`

where `val`

is a list of values. So first construct a dictionary with

```
eval_dict = dict( [ (vars[i], val[i]) for i in range(n) ] )
```

Then you can evaluate by executing

```
f( eval_dict )
```

2 | No.2 Revision |

A possible approach might be the following:

```
vars=[]
f = 0
for counter in range(1,5):
vars.append( var('x'+str(counter) ))
f += mylist[counter] * vars[counter]
```

Then you can use a dictionary to evaluate. Say you have `n`

variables and want ~~variable ~~~~i~~vars[i]~~in vars ~~to take value `val[i]`

where `val`

is a list of values. So first construct a dictionary with

```
eval_dict = dict( [ (vars[i], val[i]) for i in range(n) ] )
```

Then you can evaluate by executing

```
f( eval_dict )
```

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