How to convert letters to uppercase?

Ruby
1

Im unfamiliar with regular expressions.

How would I be able to change all letters to uppercase to the first
period?

Before:

helpuser01.hello.txt

After:

HELPUSER01.hello.txt

Any advice would be dearly appreciated.

2

Richard S. wrote in post #976947:

Im unfamiliar with regular expressions.

How would I be able to change all letters to uppercase to the first
period?

Before:

helpuser01.hello.txt

After:

HELPUSER01.hello.txt

  1. Write a regular expression to match everything before the first
    period.

  2. Substitute it with the uppercased version

str = “helpuser01.hello.txt”
str.sub!(/\A.*?./) { $&.upcase }
puts str

3

On Sun, Jan 23, 2011 at 11:24 PM, Richard S. [email protected]
wrote:

After:

HELPUSER01.hello.txt

ruby-1.9.2-p0 > a = “helpuser01.hello.txt”
=> “helpuser01.hello.txt”
ruby-1.9.2-p0 > a.sub(/.*?./) {|m| m.upcase}
=> “HELPUSER01.hello.txt”

martin

4

Perhaps much less efficient, but ‘easier’ for newbie :
a=“helpuser01.hello.txt”
a=a.split(“.”,2)
a[0]=a[0].upcase
a=a.compact.join(“.”)

Martin DeMello wrote in post #976951:

On Sun, Jan 23, 2011 at 11:24 PM, Richard S. [email protected]
wrote:

After:

HELPUSER01.hello.txt

ruby-1.9.2-p0 > a = “helpuser01.hello.txt”
=> “helpuser01.hello.txt”
ruby-1.9.2-p0 > a.sub(/.*?./) {|m| m.upcase}
=> “HELPUSER01.hello.txt”

martin

5

Hi, Richard

When the string doesn’t contain a period, you want to change all
letters to uppercase? or not?
If you want to do, the following code is not good for you:

str.sub!(/\A.*?./) { $&.upcase }

str = “hello”
str.sub!(/\A.*?./) { $&.upcase }
puts str

hello

Please use the following regexp instead:

str.sub!( /\A[^.]*/ ) { |s| s.upcase }

str = “hello”
str.sub!( /\A[^.]*/ ) { |s| s.upcase }
puts str

HELLO

Regards,