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Count

Count
gives the number of elements in list that match pattern.
Count
gives the total number of subexpressions matching pattern that appear at the levels in expr specified by levelspec.
  • Count uses standard level specifications:
nlevels 1 through n
Infinitylevels through Infinity
{n}level n only
{n1,n2}levels through
  • The default value for levelspec in Count is .
  • A positive level n consists of all parts of expr specified by n indices.
  • A negative level -n consists of all parts of expr with depth n.
  • Level -1 consists of numbers, symbols and other objects that do not have subparts.
  • Level 0 corresponds to the whole expression.
  • With the option setting Heads->True, Count looks at heads of expressions and their parts.
Count how many times occurs:
Count how many times occurs:
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Count works with patterns:
Count the number of elements not matching :
Count occurrences of down to level 2:
Count works with any head, not just List:
Count the total number of symbols in an expression:
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