Sample C# parser showing how to change text to business objects.
We are importing state of a warehouse. Every item can be located on many shelves in different quantities. We want to know what items are located on which shelf and in which quantity.
- data is streamed, line after line
- the goal is to achieve decent performance in terms of memory usage and speed
item name;item id;shelf,amount|shelf,amount|shelf,amount
| token | min length | max length | allowed characters |
|---|---|---|---|
| item name | 1 | ∞ | any character except ; |
| item id | 1 | ∞ | any character except ; |
| shelf | 1 | ∞ | any character except , and | |
| quantity | 1 | 9 | [0-9] |
- every line should contain at least one pair of (shelf, amount)
- the same pair (item,shelf) can appear in many lines, in that case we should sum quantities
- a line that starts with # is the comment and should be ignored
- some lines may be incorrectly formatted, we should detect them
- shelves should be sorted by the total number of items and then by name
- items contained on each shelf should be sorted in ascending order by ID and displayed in a format so that next to the item id the total number of items has appeared
# Inventory initial state as of Jan 27 2019
The Hunger Games (The Hunger Games, #1);978-0439023481;S-A,5|S-B,10
Harry Potter and the Order of the Phoenix;978-0439358071;S-A,15
To Kill a Mockingbird;978-0469653981;S-A,10|S-B,6|S-C,2
Pride and Prejudice;978-0679783268;S-A,10|S-B,11
The Hobbit;978-0345538376;S-C,5
The Martian;978-0804139021;
# restocked
Twilight;978-0316015844;S-C,13|S-B,5
The Book Thief;978-0375831003;S-A,10|S-B,1
Animal Farm;978-0452284241;S-C,10
The Hobbit;978-0345538376;S-C,4
Ready Player One;978-0307887436;S-A,l
S-A (total 50)
978-0375831003: 10
978-0439023481: 5
978-0439358071: 15
978-0469653981: 10
978-0679783268: 10
S-C (total 34)
978-0316015844: 13
978-0345538376: 9
978-0452284241: 10
978-0469653981: 2
S-B (total 33)
978-0316015844: 5
978-0375831003: 1
978-0439023481: 10
978-0469653981: 6
978-0679783268: 11
# Invalid lines
The Martian;978-0804139021;
Ready Player One;978-0307887436;S-A,l
Intel Core i7-9750H CPU 2.60GHz
.NET Core SDK=3.1.301| Method | Mean | Ratio | Rank | Gen 0 | Gen 1 | Gen 2 | Allocated |
|---|---|---|---|---|---|---|---|
| SpanBased | 1.044 ms | 0.26 | 1 | 173.8281 | - | - | 1074.37 KB |
| IndexBased | 1.046 ms | 0.26 | 1 | 173.8281 | - | - | 1074.34 KB |
| SpanBasedWithStringPool | 1.776 ms | 0.45 | 2 | 1.9531 | - | - | 17.36 KB |
| SplitBased | 3.956 ms | 1.00 | 3 | 804.6875 | - | - | 4968.07 KB |
| RegexBased | 9.981 ms | 2.52 | 4 | 1500.0000 | - | - | 9235.26 KB |