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Getting first index of a collection in Julia – firstindex() Methods

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The firstindex() is an inbuilt function in julia which is used to return the first index of the specified collection. If a dimension d is given, return the first index of collection along dimension d.

Syntax:
firstindex(collection)
or
firstindex(collection, d)

Parameters:

  • collection: Specified collection.
  • b: Specified dimension.

Returns: It returns the first index of the specified collection. If a dimension d is given, return the first index of collection along dimension d.

Example 1:




# Julia program to illustrate 
# the use of firstindex() method
   
# Getting the first index of the specified collection.
println(firstindex(0))
println(firstindex([1, 2, 3]))
println(firstindex([2 4; 5 6]))
println(firstindex([3; 5; 7; 9]))


Output:

Example 2:




# Julia program to illustrate 
# the use of firstindex() method
   
# Getting the first index of the specified 
# collection. If a dimension d is given, 
# return the first index of collection 
# along dimension d.
println(firstindex(rand(1, 2, 3, 4), 1))
println(firstindex(rand(1, 2, 3, 4), 2))
println(firstindex([1, 2, 3], 2))
println(firstindex([2 4; 6 8], 2))
println(firstindex([2; 4; 6; 8], 2))
println(firstindex(cat([1 2; 3 4], [5 6; 7 8], [2 2; 3 4], dims = 3);))


Output:



Last Updated : 26 Mar, 2020
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