Ruby Regular Expression: 1-2 digits required after period if period is present -

i trying create regular expression matches following:

• one or more digits
• allow 0 1 period after first digits
• if period present
  • require 1 - 2 digits after period

here regex have far, doesn't work cases:

/\d{1,}\.{0,1}\d{1,2}/ 

all of these test cases should pass

1.9 1 12 1211.1 121234.14 

all of these test cases should not pass

z z1 z.5          z.55        # no letters  .9         # required 1 or more digits before period if period present 34.         # required 1-2 digits after period if period present 4..3 4..55       # 1 period 4.333       # 1-2 digits after period 111,222.44  # no comma 

edited

i think resolve..

/^\d{1,}(\.\d{1,2}){0,1}$/ 

my test case:

2.3.0 :129 > regex = /^\d{1,}(\.\d{1,2}){0,1}$/  => /^\d{1,}(\.\d{1,2}){0,1}$/ 2.3.0 :161 > regex.match("1.9")  => #<matchdata "1.9" 1:".9">  2.3.0 :162 > regex.match("1")  => #<matchdata "1" 1:nil>  2.3.0 :163 > regex.match("12")  => #<matchdata "12" 1:nil>  2.3.0 :164 > regex.match("1211.1")  => #<matchdata "1211.1" 1:".1">  2.3.0 :165 > regex.match("121234.14")  => #<matchdata "121234.14" 1:".14">  2.3.0 :166 > regex.match("z")  => nil  2.3.0 :167 > regex.match("z1")  => nil  2.3.0 :168 > regex.match("z.5")  => nil  2.3.0 :169 > regex.match("z.55")  => nil  2.3.0 :170 > regex.match(" .9")  => nil  2.3.0 :171 > regex.match("34.")  => nil  2.3.0 :172 > regex.match("4..3")  => nil  2.3.0 :173 > regex.match("4..55")  => nil  2.3.0 :174 > regex.match("4.333")  => nil  2.3.0 :175 > regex.match("111,222.44")  => nil