linux - How to get the size of the second dimension of two dimensional arrays in bash? -

if have

arr[0,0]=0; arr[0,1]=1; 

and try

echo ${#arr[0,@]} 

i got

bash: 0,@: syntax error: operand expected (error token "@") 

what correct way size of second dimension or arr?

multi-dimensional arrays not supported in bash.
nevertheless, simulate them using various techniques.

the following definitions same:

• arr[1,10]=anything
• arr["1,10"]=anything

both evaluated arr[10]=anything (thanks chepner):

echo ${arr[10]}