0

thats what I get:

TypeError: 'float' object is unsubscriptable

Thats what I did:

import numpy as N
import itertools

#I created two lists, containing large amounts of numbers, i.e. 3.465

lx = [3.625, 4.625, ...]
ly = [41.435, 42.435, ...] #The lists are not the same size!

xy = list(itertools.product(lx,ly)) #create a nice "table" of my lists

#that iterttools gives me something like
print xy 
[(3.625, 41.435), (3.625, 42.435), (... , ..), ... ]

print xy[0][0]
print xy[0][1] #that works just fine, I can access the varios values of the tuple in the list


#down here is where the error occurs
#I basically try to access certain points in "lon"/"lat" with values from xy through `b` and `v`with that iteration. lon/lat are read earlier in the script 

b = -1
v = 1

for l in xy:
    b += 1
    idx = N.where(lon==l[b][b])[0][0]
    idy = N.where(lat==l[b][v])[0][0]

lan/lot are read earlier in the script. I am working with a netCDF file and this is the latitude/longitude,read into lan/lot. Its an array, build with numpy.

Where is the mistake? I tried to convert b and v with int() to integers, but that did not help. The N.where is accessing through the value from xy a certain value on a grid with which I want to proceed. If you need more code or some plots, let me know please.

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  • the problem is [0][0] after your where call Commented Mar 10, 2015 at 15:21
  • 1
    Where and what is lon and lat? Commented Mar 10, 2015 at 15:23
  • @user3012759 why is that a problem? Commented Mar 10, 2015 at 15:29
  • @Stophface sorry... got confused ignore my comment Commented Mar 10, 2015 at 15:32

1 Answer 1

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Your problem is that when you loop over xy, each value of l is a single element of your xy list, one of the tuples. The value of l in the first iteration of the loop is (3.625, 41.435), the second is (3.625, 42.435), and so on.

When you do l[b], you get 3.625. When you do l[b][b], you try to get the first element of 3.625, but that is a float, so it has no indexes. That gives you an error.

To put it another way, in the first iteration of the loop, l is the same as xy[0], so l[0] is the same as xy[0][0]. In the second iteration, l is the same as xy[1], so l[0] is the same as xy[1][0]. In the third iteration, l is equivalent to xy[2], and so on. So in the first iteration, l[0][0] is the same as xy[0][0][0], but there is no such thing so you get an error.

To get the first and second values of the tuple, using the indexing approach you could just do:

x = l[0]
y = l[1]

Or, in your case:

for l in xy:
    idx = N.where(lon==l[0])[0][0]
    idy = N.where(lat==l[1])[0][0]

However, the simplest solution would be to use what is called "tuple unpacking":

for x, y in xy:
    idx = N.where(lon==x)[0][0]
    idy = N.where(lat==y)[0][0]

This is equivalent to:

for l in xy:
    x, y = l
    idx = N.where(lon==x)[0][0]
    idy = N.where(lat==y)[0][0]

which in turn is equivalent to:

for l in xy:
    x = l[0]
    y = l[1]
    idx = N.where(lon==x)[0][0]
    idy = N.where(lat==y)[0][0]
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4 Comments

I understand and I dont. How would I access then 3.625 and 41.435 differently? With that one it works: xy[0][0] and xy[0][1] With xy[1] I only access (3.625, 41.435)
that's because xy != l. xy is a list of tuples whereas l is a tuple. try to access l[0][0] in the loop and it will break
I have expanded the answer to explain how to actually make it work.
Ah, now I got it! Thanks a lot for your efforts!

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