Can't figure out NameError

Question

I am trying to build a cost model using mostly if statements but I keep getting the error:

NameError: name 'spread_1' is not defined. 

I am a beginner with python so I don't know if I've done something incorrect. Please help.

#water depth of project site in metres
water_depth = 100

#platform wells require jackups
pl = 1
#1-2 complexity required LWIV
ss_simple = 1
#3-4 complexity requires rig
ss_complex = 0

#day rates
vjackup = 75000
jackup = 90000
vsemi = 170000
semi = 300000
lwiv = 200000

#determining vessel spread for platform wells
if pl >= 1:
    if water_depth == range(0, 50):
        spread_1 = vjackup * 24.1
    elif water_depth == range(51, 150):
        spread_1 = jackup * 24.1
elif pl == 0:
    spread_1 = 0

Answer 1

You should replace the == with in at the

if water_depth == range(0, 50):

and

elif water_depth == range(51, 150):

making your block of code:

if pl >= 1:
    if water_depth == range(0, 50):
        spread_1 = vjackup * 24.1
    elif water_depth == range(51, 150):
        spread_1 = jackup * 24.1
elif pl == 0:
    spread_1 = 0

into

if pl >= 1:
    if water_depth in range(0, 50):
        spread_1 = vjackup * 24.1
    elif water_depth in range(51, 150):
        spread_1 = jackup * 24.1
elif pl == 0:
    spread_1 = 0

But it would be more practical to use extreme equality operators in your case:

if pl >= 1:
    if 0 <= water_depth < 50:
        spread_1 = vjackup * 24.1
    elif 51 <= water_depth < 150:
        spread_1 = jackup * 24.1
elif pl == 0:
    spread_1 = 0

Do note that the range() function omits the end value, so range(0, 50)'s last value would be 49, not 50.