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

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:

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