CountsBy

CountsBy[{e1,e2,…},f]

キーが f[ei]の明確な値であり，値がこれらの f[ei]の値が現れる回数を与える連想を与える．

CountsBy[f]

式に適用可能なCountsByの演算子形を表す．

詳細

  • CountsBy[{e1,e2,…},f]は，キー f[ei]が対応する eiが最初に現れる順である連想を与える．
  • CountsBy[f][expr]はCountsBy[expr,f]に等しい．

例題

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例  (2)

CountsByの演算子形を使う：

特性と関係  (1)

CountsByの結果は，CountsをMapの結果に適用した結果と同じである：

Wolfram Research (2014), CountsBy, Wolfram言語関数， https://reference.wolfram.com/language/ref/CountsBy.html.

テキスト

Wolfram Research (2014), CountsBy, Wolfram言語関数， https://reference.wolfram.com/language/ref/CountsBy.html.

CMS

Wolfram Language. 2014. "CountsBy." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/CountsBy.html.

APA

Wolfram Language. (2014). CountsBy. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/CountsBy.html

BibTeX

@misc{reference.wolfram_2024_countsby, author="Wolfram Research", title="{CountsBy}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/CountsBy.html}", note=[Accessed: 21-November-2024 ]}

BibLaTeX

@online{reference.wolfram_2024_countsby, organization={Wolfram Research}, title={CountsBy}, year={2014}, url={https://reference.wolfram.com/language/ref/CountsBy.html}, note=[Accessed: 21-November-2024 ]}