CountDistinctBy
CountDistinctBy[{e1,e2,…},f]
gives the number of distinct values of f[ei] that occur.
represents an operator form of CountDistinctBy that can be applied to an expression.
Details
- CountDistinctBy[<key1val1,key2val2,…>, f] counts the distinct values of f[vali].
- CountDistinctBy[f][expr] is equivalent to CountDistinctBy[expr,f].
Examples
open all close allBasic Examples (2)
Count the number of distinct first parts:
Count the number of distinct first parts of the values of an association:
Use the operator form of CountDistinctBy:
Applications (1)
Properties & Relations (2)
CountDistinctBy[list,f] gives the same result as CountDistinct[f/@list]:
CountDistinctBy[list,f] applies the transformation f to each element, then compares the results:
CountDistinct[list,test] applies test to two elements to determine if they are equivalent:
Text
Wolfram Research (2014), CountDistinctBy, Wolfram Language function, https://reference.wolfram.com/language/ref/CountDistinctBy.html.
CMS
Wolfram Language. 2014. "CountDistinctBy." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/CountDistinctBy.html.
APA
Wolfram Language. (2014). CountDistinctBy. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/CountDistinctBy.html