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32cdc96414
This PR tries to clean up the use of `filter` by replacing it with `where`. I did not test each script. closes #1134 closes #1133
98 lines
1.7 KiB
Text
98 lines
1.7 KiB
Text
# Some examples of how you can use nushell commands to treat lists like other data structures and perform equivalent data structure operations on them.
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## Queue (first in, first out [FIFO])
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let queue = [1 2 3]
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let elem = 4
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### Enqueue (push)
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$queue | append $elem
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### Dequeue (shift)
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{ out: ($queue | first),
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new_queue: ($queue | skip 1) }
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## Stack (last in, first out [LIFO])
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### Push
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$queue | append $elem
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### Pop
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{ out: ($queue | last),
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new_stack: ($queue | drop) }
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## Set
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# Ordered sets are similar to below, just taking more care of order when altering the sets since lists are already ordered.
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let set = [1 2 3]
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let elem = 4
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let set_b = [2 3 4 5]
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### Checking set membership
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$elem in $set # false
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2 in $set # true
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### Inserting a new element
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if $elem not-in $set { $set | append $elem }
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# or
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$set | append $elem | uniq
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# Result: [1 2 3 4]
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### Union
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$set ++ $set_b | uniq
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# Result: [1 2 3 4 5]
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### Intersection
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$set | where { |elem| $elem in $set_b }
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# Result: [2 3]
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### Difference
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# $set - $set_b
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$set | where { |elem| $elem not-in $set_b }
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# or
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# Result: [1]
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### Symmetric Difference
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$set ++ $set_b | uniq --unique
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# Result: [1 4 5]
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### Multiset (bag)
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# Pretty much the same as a list but you can get the counts of the multiset elements with
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[1 2 2 3] | uniq --count
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# Result:
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# ╭───┬───────┬───────╮
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# │ # │ value │ count │
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# ├───┼───────┼───────┤
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# │ 0 │ 1 │ 1 │
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# │ 1 │ 2 │ 2 │
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# │ 2 │ 3 │ 1 │
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# ╰───┴───────┴───────╯
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# The unique values along with how many times they are in the multiset/bag.
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