Count: count
count
Count: Count items in a map, list or array
Description
Counts the number of items in a structure, be that a list, map or other object type.
count
has several modes ranging from updating values in place, returning new structures, or just outputting totals.
Usage
<stdin> -> count [ --duplications | --unique | --total ] -> <stdout>
Examples
Count number of items in a map, list or array:
» tout json (["a", "b", "c"]) -> count
3
Flags
--bytes
Count the total number of bytes read from stdin--duplications
Output a JSON map of items and the number of their occurrences in a list or array--runes
Count the total number of unicode characters (runes) read from stdin. Zero width symbols, wide characters and other non-typical graphemes are all each treated as a single rune--sum
Read an array, list or map from stdin and output the sum of all the values (ignore non-numeric values)--sum-strict
Read an array, list or map from stdin and output the sum of all the values (error on non-numeric values)--total
Read an array, list or map from stdin and output the length for that array (default behaviour)--unique
Print the number of unique elements in a list or array-b
Alias for --bytes
-d
Alias for--duplications
-r
Alias for--runes
-s
Alias for--sum
-t
Alias for--total
-u
Alias for--unique
Detail
If no flags are set, count
will default to using --total
.
--total
/ -t
Total: This will read an array, list or map from stdin and output the length for that array.
» a [25-Dec-2020..05-Jan-2021] -> count
12
This also replaces the older
len
method.
Please note that this returns the length of the array rather than string. For example out "foobar" -> count
would return 1
because an array in the str
data type would be new line separated (eg out "foo\nbar" -> count
would return 2
). If you need to count characters in a string and are running POSIX (eg Linux / BSD / OSX) then it is recommended to use wc
instead. But be mindful that wc
will also count new line characters.
» out "foobar" -> count
1
» out "foo\nbar" -> count
2
» out "foobar" -> wc: -c
7
» out "foo\nbar" -> wc: -c
8
» printf "foobar" -> wc: -c
6
# (printf does not print a trailing new line)
--duplications
/ -d
Duplications: This returns a JSON map of items and the number of their occurrences in a list or array.
For example in the quote below, only the word "the" is repeated so that entry will have a value of 2
while ever other entry has a value of 1
because they only appear once in the quote.
» out "the quick brown fox jumped over the lazy dog" -> jsplit \s -> count --duplications
{
"brown": 1,
"dog": 1,
"fox": 1,
"jumped": 1,
"lazy": 1,
"over": 1,
"quick": 1,
"the": 2
}
--unique
/ -u
Unique: Returns the number of unique elements in a list or array.
For example in the quote below, only the word "the" is repeated, thus the unique count should be one less than the total count:
» out "the quick brown fox jumped over the lazy dog" -> jsplit \s -> count --unique
8
» out "the quick brown fox jumped over the lazy dog" -> jsplit \s -> count --total
9
Synonyms
count
len
See Also
- Array Append:
append
: Add data to the end of an array - Array Prepend:
prepend
: Add data to the start of an array - Array Reverse:
mtac
: Reverse the order of an array - Array Sort:
msort
: Sorts an array - data type agnostic - Create JSON Array:
ja
: A sophisticated yet simply way to build a JSON array - Create Map:
map
: Creates a map from two data sources - Create New Array:
ta
: A sophisticated yet simple way to build an array of a user defined data-type - Create Streamable Array
a
: A sophisticated yet simple way to stream an array or list (mkarray) - Filter By Range:
[ ..Range ]
: Outputs a ranged subset of data from stdin - Get Item Property:
[ Index ]
: Outputs an element from an array, map or table - Get Nested Element:
[[ Element ]]
: Outputs an element from a nested structure - Output With Type Annotation:
tout
: Print a string to the stdout and set it's data-type - String Split:
jsplit
: Splits stdin into a JSON array based on a regex parameter - String Split:
jsplit
: Splits stdin into a JSON array based on a regex parameter
This document was generated from builtins/core/datatools/count_doc.yaml.