javascript - 为什么这个函数返回 NaN？

Question

function getNucleobaseCount (strand) {
  /*
  Returns occurences of nucleobases A and C respectively
  */
  var countA = (strand.split("A").lenght - 1);
  var countC = (strand.split("C").lenght - 1);
  return countA + " " + countC;
}

但

> console.log(getNucleobaseCount("AAGCATT"))
Nan Nan

而不是预期的3 1

为什么？

Answer 1

财产的价值lenght将是undefined。

undefined - 1是NaN

你拼错了length。

Answer 2

的拼写length错误？我认为它会显示编译错误。

Answer 3

你拼错了“长度”:-)

function getNucleobaseCount (strand) {
  /*
  Returns occurences of nucleobases A and C respectively
  */
  var countA = (strand.split("A").length - 1);
  var countC = (strand.split("C").length - 1);
  return countA + " " + countC;
}