List access, condition statements

## 1. item access

Place GhPython components like this.

For the time being, we keep using Item Access

The codes on "from" and "to" ends are:

You will get

## 2. item access

Let's switch to List Access.

Now, the "To" end component turned to Red. This is because circle is a list type object and not a tuple.
Let's modify the code a little bit.

You will get the same result as the previous one.

## 3. Gaussian hill

Surface version of the Gaussian function.

```import rhinoscriptsyntax as rs
import math
F=lambda x,y:(
A*math.exp(-((x-x0)**2+(y-y0)**2)/
(2*(C**2))))
a=list()
for i in rs.frange(-1.0,1.0,0.05):
for j in rs.frange(-1.0,1.0,0.05):
```

## 5. Gaussian hill with List Access

Let's change the access type of "hill" to List Access.
Let's rename the "hill" "hills".

Our new code for To end is

```import rhinoscriptsyntax as rs
import math

_F=lambda x,y,A,C,x0,y0:(
A*math.exp(-((x-x0)**2
+(y-y0)**2)/(2*(C**2))))
def F(x,y):
z=0
for hill in hills:
(A,C,x0,y0)=hill #Unpacking
z+=_F(x,y,A,C,x0,y0)
return z
a=list()
for i in rs.frange(-1.0,1.0,0.05):
for j in rs.frange(-1.0,1.0,0.05):
```

Note that
```F=lambda x:x**2
```

is equivalent to
```def F(x):
return x**2
```

If you duplicate From end like this

You may get somthing like this

## 6. Condition statements

```a=1
print a==1
print a==2
print a<1
print a<=1
print a!=1
```
```a=1
b=2
print a==1 and b==2
print a==1 or b==2
print a==1 and b==3
print a==1 or b==3
```
page revision: 33, last edited: 12 Nov 2013 11:08