# Python script for if/elif condition in field calculator [duplicate]

I need some help in calculating the last column (OD_pairs.Ai_) based on the condition; if travel_cost has a value below 10, OD-pairs.Ai_ takes the value of the first column(Aij_OjFCij..) if travel_cost has a value above 10, then return 0 in OD_pairs.Ai. So basically the third field to be calculated is either the corresponding value in the first field or zero, depending on the value in second field.

## marked as duplicate by Mike T, Kevin, Chris W, Evil Genius, PolyGeo♦Oct 12 '15 at 21:32

My solution is in Python, don't forget to switch to Python Parser in the Field Calculator window.

Pre-Logic Script Code:

``````def calcColumn(cost, Aji):
if cost < 10:
return Aji
elif cost > 10:
return 0
``````

OD_pairs.Ai_ =

``````calcColumn(!Travel_Cost!, !Aij_OjFCij_Income4!)
``````

Bare in mind if you have cost = 10, it won't work, as it only handles larger than or smaller than 10. You can also instead use:

Pre-Logic Script Code:

``````def calcColumn(cost, Aji):
if cost < 10:
return Aji
else:
return 0
``````
• Edit: Reread his post. It is confusing, but the code you proposed is correct. – Richard Fairhurst Oct 12 '15 at 17:50
• Alvin if it works please mark as answered. – Nir Oct 12 '15 at 18:56