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datestr - Convert date and time to string format

Syntax

S = datestr(V)
S = datestr(N)
S = datestr(D, F)
S = datestr(S1, F, P)
S = datestr(..., 'local')

Description

datestr is one of three conversion functions that enable you to express dates and times in any of three formats in your MATLAB application: a string (or date string), a vector of date and time components (or date vector), or as a numeric offset from a known date in time (or serial date number). Here is an example of a date and time expressed in the three MATLAB formats:

Date String:           '24-Oct-2003 12:45:07'
Date Vector:           [2003  10  24  12  45  07]
Serial Date Number:    7.3188e+005

A serial date number represents the whole and fractional number of days from 1-Jan-0000 to a specific date. The year 0000 is merely a reference point and is not intended to be interpreted as a real year in time.

Values outside the normal range of each unit are automatically carried to the next. For example, month values greater than 12 are carried to years. All units can wrap and have negative values, with the following caveats:

S = datestr(V) converts one or more date vectors V to date strings S. Input V must be an m-by-6 matrix containing m full (six-element) date vectors. Each element of V must be a positive double-precision number. datestr returns a column vector of m date strings, where m is the total number of date vectors in V.

S = datestr(N) converts one or more serial date numbers N to date strings S. Input argument N can be a scalar, vector, or multidimensional array of positive double-precision numbers. datestr returns a column vector of m date strings, where m is the total number of date numbers in N.

S = datestr(D, F) converts one or more date vectors, serial date numbers, or date strings D into the same number of date strings S. Input argument F is a format number or string that determines the format of the date string output. Valid values for F are given in the table Standard MATLAB Date Format Definitions, below. Input F may also contain a free-form date format string consisting of format tokens shown in the table Free-Form Date Format Specifiers, below.

Date strings with 2-character years are interpreted to be within the 100 years centered around the current year.

S = datestr(S1, F, P) converts date string S1 to date string S, applying format F to the output string, and using pivot year P as the starting year of the 100-year range in which a two-character year resides. The default pivot year is the current year minus 50 years. All date strings in S1 must have the same format.

S = datestr(..., 'local') returns the date string in the localized format that you currently have selected by means of your computer's operating system. If you leave local out of the argument list, datestr returns the date string in the default format, which is US English.

The local argument must come last in the argument sequence.

Standard MATLAB Date Format Definitions

dateform (number)

dateform (string)

Example

0

'dd-mmm-yyyy HH:MM:SS'

01-Mar-2000 15:45:17

1

'dd-mmm-yyyy'

01-Mar-2000

2

'mm/dd/yy'

03/01/00

3

'mmm'

Mar

4

'm'

M

5

'mm'

03

6

'mm/dd'

03/01

7

'dd'

01

8

'ddd'

Wed

9

'd'

W

10

'yyyy'

2000

11

'yy'

00

12

'mmmyy'

Mar00

13

'HH:MM:SS'

15:45:17

14

'HH:MM:SS PM'

3:45:17 PM

15

'HH:MM'

15:45

16

'HH:MM PM'

3:45 PM

17

'QQ-YY'

Q1-01

18

'QQ'

Q1

19

'dd/mm'

01/03

20

'dd/mm/yy'

01/03/00

21

'mmm.dd,yyyy HH:MM:SS'

Mar.01,2000 15:45:17

22

'mmm.dd,yyyy'

Mar.01,2000

23

'mm/dd/yyyy'

03/01/2000

24

'dd/mm/yyyy'

01/03/2000

25

'yy/mm/dd'

00/03/01

26

'yyyy/mm/dd'

2000/03/01

27

'QQ-YYYY'

Q1-2001

28

'mmmyyyy'

Mar2000

29 (ISO 8601)

'yyyy-mm-dd'

2000-03-01

30 (ISO 8601)

'yyyymmddTHHMMSS'

20000301T154517

31

'yyyy-mm-dd HH:MM:SS'

2000-03-01 15:45:17

Time formats like 'h:m:s', 'h:m:s.s', 'h:m pm', ... can also be part of the input array S. If you do not specify a format string F, or if you specify F as -1, the date string format defaults to the following:

1

If S contains date information only, e.g., 01-Mar-1995

16

If S contains time information only, e.g., 03:45 PM

0

If S is a date vector, or a string that contains both date and time information, e.g., 01-Mar-1995 03:45

The following table shows the string symbols to use in specifying a free-form format for the output date string. MATLAB interprets these symbols according to your computer's language setting and the current MATLAB language setting.

Free-Form Date Format Specifiers

Symbol

Interpretation

Example

yyyy

Show year in full.

1990, 2002

yy

Show year in two digits.

90, 02

mmmm

Show month using full name.

March, December

mmm

Show month using first three letters.

Mar, Dec

mm

Show month in two digits.

03, 12

m

Show month using capitalized first letter.

M, D

dddd

Show day using full name.

Monday, Tuesday

ddd

Show day using first three letters.

Mon, Tue

dd

Show day in two digits.

05, 20

d

Show day using capitalized first letter.

M, T

HH

Show hour in two digits (no leading zeros when free-form specifier AM or PM is used (see last entry in this table)).

05, 5 AM

MM

Show minute in two digits.

12, 02

SS

Show second in two digits.

07, 59

FFF

Show millisecond in three digits.

.057

AM or PM

Append AM or PM to date string (see note below).

3:45:02 PM

Remarks

A vector of three or six numbers could represent either a single date vector, or a vector of individual serial date numbers. For example, the vector [2000 12 15 11 45 03] could represent either 11:45:03 on December 15, 2000 or a vector of date numbers 2000, 12, 15, etc.. MATLAB uses the following general rule in interpreting vectors associated with dates:

To specify dates outside of this range as a date vector, first convert the vector to a serial date number using the datenum function as shown here:

datestr(datenum([1400 12 15 11 45 03]), ...
        'mmm.dd,yyyy HH:MM:SS')
ans =
   Dec.15,1400 11:45:03

To convert a nonstandard date form into a MATLAB date form, first convert the nonstandard date form to a date number, using either datenum or datevec.

Examples

Convert date vector v to a date string:

v = [2009, 4, 2, 11, 7, 18];

datestr(v)
ans =
   02-Apr-2009 11:07:18

Return the current date and time in a string using the default format, 0:

datestr(now)

ans =
   28-Mar-2005 15:36:23

Format the current date in the mm/dd/yy format. Note that you can specify this format either by number or by string.

datestr(now, 2)     -or-     datestr(now, 'mm/dd/yy')

ans =
   03/28/05

This example uses several of the free-form format specifiers. Note the difference between the number of free-form specifiers (e.g., 'dd', 'ddd', 'dddd') and the output:

str = 'Sept 13, 1986';
[datestr(str, 'ddd ') datestr(str, 'mmm dd, ''yy')]
ans =
   Sat Sep 13, '86

[datestr(str, 'dddd ') datestr(str, 'mmmm dd, yyyy')]
ans =
   Saturday September 13, 1986

Reformat the date and time, and also show milliseconds:

dt = datestr(now, 'mmmm dd, yyyy HH:MM:SS.FFF AM')
dt =
   March 28, 2005  3:37:07.952 PM

Change the pivot year and note the effect on the output:

datestr('4/16/55', 1, 1900)
ans =
   16-Apr-1955

datestr('4/16/55', 1, 2000)
ans =
   16-Apr-2055

The date below uses a nonstandard date form (month=13). Call datenum inside of datestr to get the correct return value:

datestr(datenum('13/24/88', 'mm/dd/yy'))
ans =
   24-Jan-1989

See Also

datenum, datevec, date, clock, now, datetick

  

datenumdatenum datetickdatetick

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