Programming

Date String Formats

The datenum function is important for doing date calculations efficiently. datenum takes an input string in any of several formats, with 'dd-mmm-yyyy', 'mm/dd/yyyy', or 'dd-mmm-yyyy, hh:mm:ss.ss' most common. You can form up to six fields from letters and digits separated by any other characters:

• The day field is an integer from 1 to 31.
• The month field is either an integer from 1 to 12 or an alphabetic string with at least three characters.
• The year field is a nonnegative integer: if only two digits are specified, then a year 19yy is assumed; if the year is omitted, then the current year is used as a default.
• The hours, minutes, and seconds fields are optional. They are integers separated by colons or followed by 'AM' or 'PM'.

For example, if the current year is 1996, then these are all equivalent:

• '17-May-1996'
  '17-May-96'
  '17-May'
  'May 17, 1996'
  '5/17/96'
  '5/17'
  

and both of these represent the same time:

• '17-May-1996, 18:30'
  '5/17/96/6:30 pm'
  

Note that the default format for numbers-only input follows the American convention. Thus 3/6 is March 6, not June 3.

If you create a vector of input date strings, use a column vector and be sure all strings are the same length. Fill in with spaces or zeros.

Conversions Between Date Formats

Output Formats

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