namefreq.frink

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// Program to calculate the probability of a given first and last name.

firstName = input["Enter first name(s): "]
lastName = input["Enter last name: "]

pop = input["Enter population [260 million]: "]
if pop == ""
   pop = 260 million
else
   pop = eval[pop]

println["\nProbability of name \"" + firstName + " " + lastName + "\": "]

firstFreq = frequency[firstName]
println["Frequency of " + firstName + " (in either sex) is: " + (firstFreq -> "percent")]

lastFreq = frequency[lastName, false]
println["Frequency of " + lastName + " is: " + (lastFreq -> "percent")]

if lastFreq == 0
   println["Probability of last name is too low for prediction."]
else
{
   together = firstFreq * lastFreq

   //println[together -> "percent"]

   println["\nThis name is held by 1 in " + ceil[1/together] + " people."]

   println["This name will occur with probability " + (probTogether[firstFreq, lastFreq, pop] -> "percent") + " in " + pop + " people."]

   println["This name will tend to occur at least once in every " + predictTogether[firstFreq, lastFreq] + " people."]

   println["There are probably " + 10 * round[together * pop, .1] + " people with this name in " + pop + " people."]

   // Functions used by above program

   // Probability of a single name with frequency freq being in a movie with
   // chars characters...
   probAlone[freq, chars] := 1 - (1-freq)^chars

   // Probability those two names appear together in n people
   probTogether[probA, probB, pop] := 1 - (1 - probA * probB)^pop

   // Predict the number of movies to get a 50% probability
   predictTogether[probA, probB] := ceil[- ln[2] / ln[1 - probA * probB]]
}

// Contact www.placesnamed.com and fetch probabilities.
frequency[names, first=true] :=
{
   nameList = split[%r/[\s,\/]+/, names]
   freq = 0
   for [name] nameList
   {
      if (name == "")
         next          // Ignore leading/trailing space
      
      [let1, let2] = name =~ %r/(.)(.)/  // Get first 2 letters
      url = "http://www.placesnamed.com/"+ let1 + "/" + let2 + "/" + name + ".asp"

      if (first)
      {
         pattern = regex[name + ".* popular ((?:fe)?male).*frequency is (.*?)%","i"]
         for [line] lines[url]
            if [sex, p] = line =~ pattern
            {
               println[name + " (" + sex + "): " + p + "%"]
               freq = freq + eval[p] percent
            }
      } else   // Last name
      {
         pattern = regex[name + ".* popular .*last.*frequency is (.*?)%","i"]

         for [line] lines[url]
            if [p] = line =~ pattern
               freq = freq + eval[p] percent
      }
   }

   if (first)
      return freq/2
   else
      return freq
}


Download or view namefreq.frink in plain text format

This is a program written in the programming language Frink.
For more information, view the Frink Documentation or see More Sample Frink Programs.

Alan Eliasen was born 20217 days, 23 hours, 27 minutes ago.