Capitalization of strings

Let us imagine, that we have a simple abstract input form, whose aim is accepting some string, which could consist of any characters.

string = "mystical characters"

We need to process this string by making first character uppercased. Yes, that is our main goal. Thereafter we need to display this converted string in some abstract view template. So, the question is: do we really need to check whether the first character is already written correctly (uppercased) or we are able to write just this?

theresult = string.capitalize
=> "Mystical characters"

Which approach is better: 开发者_运维知识库check and then capitalize (if need) or force capitalization?

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Check first if you need to process something, because String#capitalize doesn't only convert the first character to uppercase, but it also converts all other characters downcase. So..

"First Lastname".capitalize == "First lastname"

That might not be the wanted result.

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If I understood correctly you are going to capitalize the string anyway, so why bother checking if it's already capitalized?

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Based on Tonttu answer I would suggest not to worry too much and just capitalize like this:

new_string = string[0...1].capitalize + string[1..-1]

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I ran in to Tonttu's problem importing a bunch of names, I went with:

  strs = "first lastname".split(" ")
  return_string = ""
  strs.each do |str|
    return_string += "#{str[0].upcase}#{str[1..str.length].downcase} "
  end
  return_string.chop

EDIT: The inevitable refactor (over a year) later.

  "first lastname".split(" ").map do |str| 
    "#{str[0].upcase}#{str[1..str.length].downcase}"
  end.join(' ')

while definitely not easier to read, it gets the same result while declaring fewer temporary variables.

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I guess you could write something like:

string.capitalize unless string =~ /^[A-Z].*/

Personally I would just do

string.capitalize

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Unless you have a flag to be set for capitalized strings which you going to check than just capitalize without checking.

Also the capitalization itself is probably performing some checking.