^b?0*([1-9]\d{0,3}|10\d{2} )$
it will accept from 1-9999 preceding any times zero. i.e . it will accept 0000001, 1, 1199, 9999, 0001199, 01000.
it will not accept 0, 0000, 00000, 10000, -100, -1, -9999, 10001, ab100, 100ab etc.
it can be verified from this tool http://tools.netshiftm edia.com/regexlibrary/#
it will accept from 1-9999 preceding any times zero. i.e . it will accept 0000001, 1, 1199, 9999, 0001199, 01000.
it will not accept 0, 0000, 00000, 10000, -100, -1, -9999, 10001, ab100, 100ab etc.
it can be verified from this tool http://tools.netshiftm edia.com/regexlibrary/#
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