Convert the first letter of a string to uppercase after a given separator-CodePudding

I would like the first letter after : to be uppercase using regex.

My String: order:user:name

Expected: Order:User:Name

CodePudding user response：

Regular expressions are very powerful and useful in many languages, but also complicated and hard to maintain if you don't fully grasp them. This is a sample without Regex. It produces the expected result, so the first word is capitalized, although it is not preceded by a ":".

my_str = "order:user:name"
new_str = my_str.split(":").map(&:capitalize).join(":")

CodePudding user response：

Use a look-back for either the start of the string or a ":" like so (in IRB):

> my_str="order:user:name"
=> "order:user:name"
> my_str.gsub(/(?<=^|:)([a-z])/){|c| c.upcase}
=> "Order:User:Name"

CodePudding user response：

You can use this simple regex:

:[a-z]

This means, the character : followed by any lowercase letter from a to z. Then you can use the gsub method, such as in the following example:

"aa:gfdhdf:bbb".capitalize.gsub(/:[a-z]/) {|s| s[0]   s[1].upcase}