How to change text elements in d3?

Question

Why the d is not an object? and how I can access those text objects? (The following code is wrong)

d3.selectAll("svg text").each(function(d, i) {

        d.text("New");
});

Answer 1

Inside the callback provided to .each() the parameter d will refer to the data bound to the element. You should use this instead which refers to the current element of the iteration. To wrap this into a D3 selection you need to do d3.select(this). This will change your snippet to

d3.selectAll("svg text").each(function(d, i) {
  d3.select(this).text("New");
});

That said, there is an even more concise and elegant way of achieving the same thing where D3 will do the iteration for you without the need to explicitly call .each():

d3.selectAll("svg text").text("New");

To selectivly edit texts which satisfiy some condition, as mentioned in one of your comments, you could use selection.filter():

d3.selectAll("svg text")
  .filter(function() {
    return /^C/.test(d3.select(this).text());  // Check if text begin with a "C"
  })
  .text("New");

This will preselect all texts starting with a "C" and change the textual content of these texts only.