Some common functions for arrays

If b = [1:7] and c = [100,200,300], then you can concatenate b and c with the following command:

append!(b, c) #> Now b is [1, 2, 3, 4, 5, 6, 7, 100, 200, 300] 

The array, b, is changed by applying this append! method—that's why it ends in an exclamation mark (!). This is a general convention.

A function whose name ends in a ! changes its first argument.

Likewise, push! and pop! append one element at the end, or take one away and return that, while the array is changed:

pop!(b) #> 300, b is now [1, 2, 3, 4, 5, 6, 7, 100, 200] 
push!(b, 42) # b is now [1, 2, 3, 4, 5, 6, 7, 100, 200, 42]  

If you want to do the same operations on the front of the array, use popfirst! and pushfirst! (formerly unshift! and shift! ...

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