obsidian插件dataview官方文档翻译

# 每天回顾
# 每天
日期:: 2020-08-15
评级:: 7.5
起床:: 10:30am
睡觉:: 12:30am

```dataview
table 日期, 评级, 起床, 睡觉 from #每天 
```

---
duration: 4 hours
reviewed: false
---
# Movie X

**Thoughts**:: It was decent.
**Rating**:: 6

```dataview
... query ...
```

`= <query language expression>`

```dataviewjs
... js code ...
```

```dataview
TABLE|LIST|TASK <field> [AS "Column Name"], <field>, ..., <field> FROM <source> (like #tag or "folder")
WHERE <expression> (like 'field = value')
SORT <expression> [ASC/DESC] (like 'field ASC')
... other data commands
```

LIST FROM <source>

LIST <expression> FROM <source>

TABLE file.cday, file.mtime FROM #每天

TABLE (file.mtime + dur(1 day)) AS next_mtime, ... FROM <source>

table 日期, 评级, 起床, 睡觉 from #每天 
SORT 评级 DESC

TASK from <source>

WHERE <clause>

LIST WHERE file.mtime >= date(today) - dur(1 day)

LIST FROM #projects
WHERE !completed AND file.ctime <= date(today) - dur(1 month)

SORT date [ASCENDING/DESCENDING/ASC/DESC]

SORT field1 [ASCENDING/DESCENDING/ASC/DESC], ..., fieldN [ASC/DESC]

GROUP BY field
GROUP BY (computed_field) AS name

FLATTEN field
FLATTEN (computed_field) AS name

table authors from #LiteratureNote
flatten authors

# 常规
field               (directly refer to a field)
simple-field        (refer to fields with spaces/punctuation in them like "Simple Field!")
a.b                 (if a is an object, retrieve field named 'b')
a[expr]             (if a is an object or array, retrieve field with name specified by expression 'expr')
f(a, b, ...)        (call a function called `f` on arguments a, b, ...)

# 算术运算
a + b               (addition)
a - b               (subtraction)
a * b               (multiplication)
a / b               (division)

# 比较运算
a > b               (check if a is greater than b)
a < b               (check if a is less than b)
a = b               (check if a equals b)
a != b              (check if a does not equal b)
a <= b              (check if a is less than or equal to b)
a >= b              (check if a is greater than or equal to b)

# 特殊操作
[[Link]].value      (fetch `value` from page `Link`)

lower("YES") = "yes"
lower(list("YES", "NO")) = list("yes", "no")

replace("yes", "e", "a") = "yas"
replace(list("yes", "ree"), "e", "a") = list("yas", "raa")

object() => empty object
object("a", 6) => object which maps "a" to 6
object("a", 4, "c", "yes") => object which maps a to 4, and c to "yes"

list() => empty list
list(1, 2, 3) => list with 1, 2, and 3
list("a", "b", "c") => list with "a", "b", and "c"

date("2020-04-18") = <date object representing April 18th, 2020>
date([[2021-04-16]]) = <date object for the given page, refering to file.day>

number("18 years") = 18
number(34) = 34
number("hmm") = null

link("Hello") => link to page named 'Hello'
link("Hello", "Goodbye") => link to page named 'Hello', displays as 'Goodbye'

elink("www.google.com") => link element to google.com
elink("www.google.com", "Google") => link element to google.com, displays as "Google"

round(16.555555) = 17
round(16.555555, 2) = 16.56

extract(file, "ctime", "mtime") = object("ctime", file.ctime, "mtime", file.mtime)
extract(object("test", 1)) = object()

sort(list(3, 2, 1)) = list(1, 2, 3)
sort(list("a", "b", "aa")) = list("a", "aa", "b")

reverse(list(1, 2, 3)) = list(3, 2, 1)
reverse(list("a", "b", "c")) = list("c", "b", "a")

length(list()) = 0
length(list(1, 2, 3)) = 3
length(object("hello", 1, "goodbye", 2)) = 2

sum(list(1, 2, 3)) = 6

all(list(1, 2, 3)) = true
all(list(true, false)) = false
all(true, false) = false
all(true, true, true) = true

any(list(1, 2, 3)) = true
any(list(true, false)) = true
any(list(false, false, false)) = false
all(true, false) = true
all(false, false) = false

join(list(1, 2, 3)) = "1, 2, 3"
join(list(1, 2, 3), " ") = "1 2 3"
join(6) = "6"
join(list()) = ""

regexmatch("\w+", "hello") = true
regexmatch(".", "a") = true
regexmatch("yes|no", "maybe") = false

regexreplace("yes", "[ys]", "a") = "aea"
regexreplace("Suite 1000", "\d+", "-") = "Suite -"

replace("what", "wh", "h") = "hat"
replace("The big dog chased the big cat.", "big", "small") = "The small dog chased the small cat."
replace("test", "test", "no") = "no"

lower("Test") = "test"
lower("TEST") = "test"

upper("Test") = "TEST"
upper("test") = "TEST"

default(dateCompleted, "incomplete")

default(list(1, 2, null), 3) = list(1, 2, 3)
ldefault(list(1, 2, null), 3) = list(1, 2, null)

choice(true, "yes", "no") = "yes"
choice(false, "yes", "no") = "no"
choice(x > 4, y, z) = y if x > 4, else z

striptime(file.ctime) = file.cday
striptime(file.mtime) = file.mday

```dataview
TABLE time-played, length, rating FROM "games"
SORT rating DESC
```

```dataview
LIST FROM #game/moba or #game/crpg
```

```dataview
TASK FROM #projects/active
```

```dataview
TABLE file.mtime FROM "books"
SORT file.mtime DESC
```

```dataview
LIST file.day WHERE file.day
SORT file.day DESC
```

```dataviewjs
<code>
```

/** A function which maps an array element to some value. */
export type ArrayFunc<T, O> = (elem: T, index: number, arr: T[]) => O;

/** A function which compares two types (plus their indices, if relevant). */
export type ArrayComparator<T> = (a: T, b: T) => number;

/**
 * Proxied interface which allows manipulating array-based data. All functions on a data array produce a NEW array
 * (i.e., the arrays are immutable).
 */
export interface DataArray<T> {
    /** The total number of elements in the array. */
    length: number;

    /** Filter the data array down to just elements which match the given predicate. */
    where(predicate: ArrayFunc<T, boolean>): DataArray<T>;
    /** Alias for 'where' for people who want array semantics. */
    filter(predicate: ArrayFunc<T, boolean>): DataArray<T>;

    /** Map elements in the data array by applying a function to each. */
    map<U>(f: ArrayFunc<T, U>): DataArray<U>;
    /** Map elements in the data array by applying a function to each, then flatten the results to produce a new array. */
    flatMap<U>(f: ArrayFunc<T, U[]>): DataArray<U>;
    /** Mutably change each value in the array, returning the same array which you can further chain off of. */
    mutate(f: ArrayFunc<T, any>): DataArray<any>;

    /** Limit the total number of entries in the array to the given value. */
    limit(count: number): DataArray<T>;
    /**
     * Take a slice of the array. If `start` is undefined, it is assumed to be 0; if `end` is undefined, it is assumbed
     * to be the end of the array.
     */
    slice(start?: number, end?: number): DataArray<T>;
    /** Concatenate the values in this data array with those of another data array. */
    concat(other: DataArray<T>): DataArray<T>;

    /** Return the first index of the given (optionally starting the search) */
    indexOf(element: T, fromIndex?: number): number;
    /** Return the first element that satisfies the given predicate. */
    find(pred: ArrayFunc<T, boolean>): T | undefined;
    /** Find the index of the first element that satisfies the given predicate. Returns -1 if nothing was found. */
    findIndex(pred: ArrayFunc<T, boolean>): number;
    /** Returns true if the array contains the given element, and false otherwise. */
    includes(element: T): boolean;

    /**
     * Return a sorted array sorted by the given key; an optional comparator can be provided, which will
     * be used to compare the keys in leiu of the default dataview comparator.
     */
    sort<U>(key: ArrayFunc<T, U>, direction?: 'asc' | 'desc', comparator?: ArrayComparator<U>): DataArray<T>;

    /**
     * Return an array where elements are grouped by the given key; the resulting array will have objects of the form
     * { key: <key value>, rows: DataArray }.
     */
    groupBy<U>(key: ArrayFunc<T, U>, comparator?: ArrayComparator<U>): DataArray<{ key: U, rows: DataArray<T> }>;

    /**
     * Return distinct entries. If a key is provided, then rows with distinct keys are returned.
     */
    distinct<U>(key?: ArrayFunc<T, U>, comparator?: ArrayComparator<U>): DataArray<T>;

    /** Return true if the predicate is true for all values. */
    every(f: ArrayFunc<T, boolean>): boolean;
    /** Return true if the predicate is true for at least one value. */
    some(f: ArrayFunc<T, boolean>): boolean;
    /** Return true if the predicate is FALSE for all values. */
    none(f: ArrayFunc<T, boolean>): boolean;

    /** Return the first element in the data array. Returns undefined if the array is empty. */
    first(): T;
    /** Return the last element in the data array. Returns undefined if the array is empty. */
    last(): T;

    /** Map every element in this data array to the given key, and then flatten it.*/
    to(key: string): DataArray<any>;
    /**
     * Recursively expand the given key, flattening a tree structure based on the key into a flat array. Useful for handling
     * heirarchical data like tasks with 'subtasks'.
     */
    expand(key: string): DataArray<any>;

    /** Run a lambda on each element in the array. */
    forEach(f: ArrayFunc<T, void>): void;

    /** Convert this to a plain javascript array. */
    array(): T[];

    /** Allow iterating directly over the array. */
    [Symbol.iterator](): Iterator<T>;

    /** Map indexes to values. */
    [index: number]: any;
    /** Automatic flattening of fields. */
    [field: string]: any;
}

```dataviewjs
dv.table([], ...)
```

dv.pages("#books") => all pages with tag 'books'
dv.pages('"folder"') => all pages from folder "folder"
dv.pages("#yes or -#no") => all pages with tag #yes, or which DON'T have tag #no

dv.pagePaths("#books") => the paths of pages with tag 'books'

dv.page("Index") => The page object for /Index
dv.page("books/The Raisin.md") => The page object for /books/The Raisin.md

dv.header(1, "Big!");
dv.header(6, "Tiny");

dv.paragraph("This is some text");

dv.list([1, 2, 3]) => list of 1, 2, 3
dv.list(dv.pages().file.name) => list of all file names
dv.list(dv.pages().file.link) => list of all file links
dv.list(dv.pages("#book").where(p => p.rating > 7)) => list of all books with rating greater than 7

// List all tasks from pages marked '#project'
dv.taskList(dv.pages("#project").file.tasks)

// List all *uncompleted* tasks from pages marked #project
dv.taskList(dv.pages("#project").file.tasks
    .where(t => !t.completed))

// List all tasks tagged with '#tag' from pages marked #project
dv.taskList(dv.pages("#project").file.tasks
    .where(t => t.text.includes("#tag")))

// Render a simple table of book info sorted by rating.
dv.table(["File", "Genre", "Time Read", "Rating"], dv.pages("#book")
    .sort(b => b.rating)
    .map(b => [b.file.link, b.genre, b["time-read"], b.rating]))

dv.array([1, 2, 3]) => dataview data array [1, 2, 3]

dv.compare(1, 2) = -1
dv.compare("yes", "no") = 1
dv.compare({ what: 0 }, { what: 0 }) = 0

dv.equal(1, 2) = false
dv.equal(1, 1) = true

for (let group of dv.pages("#book").groupBy(p => p.genre)) {
    dv.header(3, group.key);
    dv.table(["Name", "Time Read", "Rating"],
        group.rows
            .sort(k => k.rating, 'desc')
            .map(k => [k.file.link, k["time-read"], k.rating]))
}