Question

I have an array and a string:

$header = ["Date", "Time", "Site Name", "Computer Name"]
columnName = "esfjk sdhf sdf"

and I am checking if $header contains columnName:

return if $header.include? columnName == false

The condition above always returns true, and the code carries on, even though the array doesn’t contain the string.

I also have the same issue when $hash is a hash and recordNum is a number such as 99999999 which is not in it, and I do:

return if $hash.has_key? recordNum == false

Any reason for this happening?

Answer 1

Precedence.

$header.include? columnName == false

is interpreted as

$header.include?(columnName == false)

that is, usually,

$header.include?(false)

which is false. So what you want to do instead is this:

$header.include?(columnName) == false

But in your particular case, I would do this (thanks, Alex Wayne):

return unless $header.include?(columnName)

And if you do that, then you can go back to the parentheses-less form:

return unless $header.include? columnName