[ncl-talk] *ListIndex*: 1D array only

[Liang Guo]

Hello,

I try to use *ListIndex* to retrieve the index of a named variable (2-D)
that has been pushed into a List variable. But, it failed.

Then, I spent some time to explore the reason. I start with a simple 1-D
example that is gave by NCL webpage (
http://www.ncl.ucar.edu/Document/Functions/Built-in/ListIndex.shtml). It
does what it does. However, when I expended those example arrays into 2-D,
function *ListIndes* collapsed. Here are what I did and what output shows:


*> ; for 1D, it works fine*
*>   x = (/1,2,3,4/)*
*>   x at attr = "integer array"*
*>   y = (/6.,7.,8.,9./)*
*>   y at attr = "float array"*
*>   s = (/"one","two","three"/)*
*>   s at attr = "string array"**> *

*>   my_list = NewList("lifo")**> *

*>   ListPush(my_list,x)*
*>   ListPush(my_list,y)*
*>   ListPush(my_list,s)**> *

*>   cnt = ListCount(my_list)*
*>   print(cnt)**> *

*>   idx = ListIndex(my_list, x)*
*>   print(idx)**> *

*> ; For 2D*
*>   nx    = dimsizes ( x )**>  **X     = conform_dims ( (/2,nx/), x, 1 )*

*>   ny    = dimsizes ( y )**>   Y     = conform_dims ( (/2,ny/), y, 1 )*

*>   ns    = dimsizes ( s )*
*>   S     = conform_dims ( (/2,ns/), s, 1 )**> *

*>   MY_list = NewList("lifo")**> *

*>   ListPush(MY_list,X)*
*>   ListPush(MY_list,Y)*
*>   ListPush(MY_list,S)**> *

*>   Cnt = ListCount(MY_list)*
*>   print(Cnt)**> *

*>   Idx = ListIndex(MY_list, X)**>   print(Idx)*

And the output is:



*> Variable: cnt> Type: integer*
*> Total Size: 4 bytes*
*>             1 values*
*> Number of Dimensions: 1*
*> Dimensions and sizes:   [1]*
*> Coordinates: *
*> (0)     3**> *

*> *
*> Variable: idx*
*> Type: integer*
*> Total Size: 4 bytes*
*>             1 values*
*> Number of Dimensions: 1*
*> Dimensions and sizes:   [1]*
*> Coordinates: *
*> (0)     2**> *

*> *
*> Variable: Cnt*
*> Type: integer*
*> Total Size: 4 bytes*
*>             1 values*
*> Number of Dimensions: 1*
*> Dimensions and sizes:   [1]*
*> Coordinates: *
*> (0)     3*
*> fatal:Number of dimensions in parameter (1) of (ListIndex) is (2), (1)
dimensions were expected *
*> fatal:["Execute.c":8578]:Execute: Error occurred at or near line 40 in
file test_ListIndex.ncl**> *

*> fatal:Variable (Idx) is undefined**> fatal:["Execute.c":8578]:Execute:
Error occurred at or near line 41 in file test_ListIndex.ncl*

As shown in the 4th line from the bottom of the output, *ListIndex* expects
a 1-D array, while a 2-D array is fed in, it does not retrieve anything and
collapse.

Any idea about this?

Best,
Liang
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