strftime – Format Date Time in Ruby

strftime – Format Date Time in Ruby ?


In Ruby, you have to format or convert time from one format to other many a times. You can use library method strftime available to perform formatting operations.

Syntax of strftime: strftime( format )
Returns: Result in requested format

First of all, let us create a new variable in which we get current time to be formatted in various formats,

t = Time.now
=> 2013-09-12 22:49:27 +0530

Now, we have variable t holding current time value, now below are the examples of,
Most Commonly used formats
Code     Output     Description
t.strftime("%H")     => "22"     # Gives Hour of the time in 24 hour clock format
t.strftime("%I")     => "10"     # Gives Hour of the time in 12 hour clock format
t.strftime("%M")     => "49"     # Gives Minutes of the time
t.strftime("%S")     => "27"     # Gives Seconds of the time
t.strftime("%Y")     => "2013"     # Gives Year of the time
t.strftime("%m")     => "09"     # Gives month of the time
t.strftime("%d")     => "12"     # Gives day of month of the time
t.strftime("%w")     => "4"     # Gives day of week of the time
t.strftime("%a")     => "Thu"     # Gives name of week day in short form of the
t.strftime("%A")     => "Thursday"     # Gives week day in full form of the time
t.strftime("%b")     => "Sep"     # Gives month in short form of the time
t.strftime("%B")     => "September"     # Gives month in full form of the time
t.strftime("%y")     => "13"     # Gives year without century of the time
t.strftime("%Y")     => "2013"     # Gives year without century  of the time
t.strftime("%Z")     => "IST"     # Gives Time Zone of the time
t.strftime("%p")     => "PM"     # Gives AM / PM of the time

These are the almost all formats that are required.
Combinations:

You can try these formats in combination too,
For example,

t.strftime("%H:%M:%S")

 => "22:49:27"
Code to print all formats


# Function to print strftime results
def print_strftime_formats(a,cur_date)
 a.each do |format|
   b = "%#{format}"
   output = cur_date.strftime(b)
   puts "t.strftime('#{b}'), => #{output}"
 end
end

a = ('a'..'z').to_a
A = ('A'..'Z').to_acur_date = Time.now

# calling and printing strftime results on current date

puts "DateTime: #{cur_date}\n"

puts "\n\nFor a to z"
print_strftime_formats(a,cur_date)

puts "\n\nFor A to Z"
print_strftime_formats(A,cur_date)

You can refer code at Github OR download this code.
The output of the above code is given below for the reference:
For 'a' to 'z'
Code     Output
t.strftime('%a')     => Thu
t.strftime('%b')     => Jan
t.strftime('%c')     => Thu Jan 23 16:38:02 2014
t.strftime('%d')     => 23
t.strftime('%e')     => 23
t.strftime('%f')     => %f # Not Useful
t.strftime('%g')     => 14
t.strftime('%h')     => Jan
t.strftime('%i')     => %i # Not Useful
t.strftime('%j')     => 023
t.strftime('%k')     => 16
t.strftime('%l')     => 4
t.strftime('%m')     => 01
t.strftime('%n')     => # Not Useful
t.strftime('%o')     => %o
t.strftime('%p')     => PM
t.strftime('%q')     => %q
t.strftime('%r')     => 04:38:02 PM
t.strftime('%s')     => 1390475282
t.strftime('%t')     => # Not Useful
t.strftime('%u')     => 4
t.strftime('%v')     => 23-JAN-2014
t.strftime('%w')     => 4
t.strftime('%x')     => 01/23/14
t.strftime('%y')     => 14
t.strftime('%z')     => +0530
For 'A' to 'Z'
Code     Output
t.strftime('%A')     => Thursday
t.strftime('%B')     => January
t.strftime('%C')     => 20
t.strftime('%D')     => 01/23/14
t.strftime('%E')     => %E # Not Useful
t.strftime('%F')     => 2014-01-23
t.strftime('%G')     => 2014
t.strftime('%H')     => 16
t.strftime('%I')     => 04
t.strftime('%J')     => %J # Not Useful
t.strftime('%K')     => %K # Not Useful
t.strftime('%L')     => 485
t.strftime('%M')     => 38
t.strftime('%N')     => 485141000
t.strftime('%O')     => %O # Not Useful
t.strftime('%P')     => pm
t.strftime('%Q')     => %Q # Not Useful
t.strftime('%R')     => 16:38
t.strftime('%S')     => 02
t.strftime('%T')     => 16:38:02
t.strftime('%U')     => 03
t.strftime('%V')     => 04
t.strftime('%W')     => 03
t.strftime('%X')     => 16:38:02
t.strftime('%Y')     => 2014
t.strftime('%Z')     => IST

So, you can tweak your format as output required for your purpose. I guess, Formatting of time is easy for you now.