Iterators: Difference between revisions
Content added Content deleted
m (J: improve grammar slightly) |
m (J: show more detail about trailing empty example) |
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col=: '' ]F..(,<) ;:'red orange yellow green blue purple' |
col=: '' ]F..(,<) ;:'red orange yellow green blue purple' |
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</lang> |
</lang> |
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<lang J> col |
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┌──────┬───────────────────────────────────────┐ |
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│purple│┌────┬────────────────────────────────┐│ |
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│ ││blue│┌─────┬────────────────────────┐││ |
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│ ││ ││green│┌──────┬───────────────┐│││ |
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│ ││ ││ ││yellow│┌──────┬──────┐││││ |
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│ ││ ││ ││ ││orange│┌───┬┐│││││ |
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│ ││ ││ ││ ││ ││red│││││││ |
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│ ││ ││ ││ ││ │└───┴┘│││││ |
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│ ││ ││ ││ │└──────┴──────┘││││ |
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│ ││ ││ │└──────┴───────────────┘│││ |
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│ ││ │└─────┴────────────────────────┘││ |
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│ │└────┴────────────────────────────────┘│ |
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└──────┴───────────────────────────────────────┘</lang> |
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This creates an issue that a single element nested list looks very much like a flat array. To prevent that from being a problem, we include an empty element at the end of our flat array: |
This creates an issue that a single element nested list looks very much like a flat array. To prevent that from being a problem, we include an empty element at the end of our flat array: |
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dow=: a:,~;:'monday tuesday wednesday thursday friday saturday sunday' |
dow=: a:,~;:'monday tuesday wednesday thursday friday saturday sunday' |
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</lang> |
</lang> |
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<lang J> dow |
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┌──────┬───────┬─────────┬────────┬──────┬────────┬──────┬┐ |
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│monday│tuesday│wednesday│thursday│friday│saturday│sunday││ |
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└──────┴───────┴─────────┴────────┴──────┴────────┴──────┴┘</lang> |
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Now everything is the same as before, except that we need to explicitly ignore the empty trailing element: |
Now everything is the same as before, except that we need to explicitly ignore the empty trailing element: |
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