Help with dates please

[jedibrown]

Hi, I was just wondering whether there was a formula to change a date once per week.

For example, instead of using =today() is there a way that I can make the date stay on a Friday until the following one.

So tomorrow it would change to 16/12/11 and stay like that until next Friday when it would change to 23/12/11 and so on.

This is because I am trying to put in "week beginning" but my week begins on a Friday. Thanks

 

[MrKowz]

MrKowz, is there something different about the weekday function in Excel versions 2007 up?

It would appear that way. I am using Excel 2010. Doing some quick research to find out when it changed:

<b>Excel 2010</b><table cellpadding="2.5px" rules="all" style=";background-color: #FFFFFF;border: 1px solid;border-collapse: collapse; border-color: #BBB"><colgroup><col width="25px" style="background-color: #DAE7F5" /><col /><col /><col /></colgroup><thead><tr style=" background-color: #DAE7F5;text-align: center;color: #161120"><th></th><th>A</th><th>B</th><th>C</th></tr></thead><tbody><tr ><td style="color: #161120;text-align: center;">1</td><td style=";">Date</td><td style=";">MrKowz</td><td style=";">P45cal</td></tr><tr ><td style="color: #161120;text-align: center;">2</td><td style="text-align: right;;">Tue 13 Dec 2011</td><td style="text-align: right;;">Fri 9 Dec 2011</td><td style="text-align: right;;">Fri 9 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">3</td><td style="text-align: right;;">Wed 14 Dec 2011</td><td style="text-align: right;;">Fri 9 Dec 2011</td><td style="text-align: right;;">Fri 9 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">4</td><td style="text-align: right;;">Thu 15 Dec 2011</td><td style="text-align: right;;">Fri 9 Dec 2011</td><td style="text-align: right;;">Fri 9 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">5</td><td style="text-align: right;;">Fri 16 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">6</td><td style="text-align: right;;">Sat 17 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">7</td><td style="text-align: right;;">Sun 18 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">8</td><td style="text-align: right;;">Mon 19 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">9</td><td style="text-align: right;;">Tue 20 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">10</td><td style="text-align: right;;">Wed 21 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">11</td><td style="text-align: right;;">Thu 22 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td><td style="text-align: right;;">Fri 16 Dec 2011</td></tr><tr ><td style="color: #161120;text-align: center;">12</td><td style="text-align: right;;">Fri 23 Dec 2011</td><td style="text-align: right;;">Fri 23 Dec 2011</td><td style="text-align: right;;">Fri 23 Dec 2011</td></tr></tbody></table><p style="width:3.6em;font-weight:bold;margin:0;padding:0.2em 0.6em 0.2em 0.5em;border: 1px solid #BBB;border-top:none;text-align: center;background-color: #DAE7F5;color: #161120">Sheet2</p><br /><br /><table width="85%" cellpadding="2.5px" rules="all" style=";border: 2px solid black;border-collapse:collapse;padding: 0.4em;background-color: #FFFFFF" ><tr><td style="padding:6px" ><b>Worksheet Formulas</b><table cellpadding="2.5px" width="100%" rules="all" style="border: 1px solid;text-align:center;background-color: #FFFFFF;border-collapse: collapse; border-color: #BBB"><thead><tr style=" background-color: #DAE7F5;color: #161120"><th width="10px">Cell</th><th style="text-align:left;padding-left:5px;">Formula</th></tr></thead><tbody><tr><th width="10px" style=" background-color: #DAE7F5;color: #161120">B2</th><td style="text-align:left">=A2-WEEKDAY(<font color="Blue">A2,15</font>)+1</td></tr><tr><th width="10px" style=" background-color: #DAE7F5;color: #161120">C2</th><td style="text-align:left">=A2-MOD(<font color="Blue">A2+1,7</font>)</td></tr></tbody></table></td></tr></table><br />

 

[MrKowz]

Quick research showed that this change was made in Excel 2010. Thank you for catching that, P45cal.

 

[barry houdini]

=A1-WEEKDAY(A1,15)+1

easily modifiable for earlier versions, both of these will do the same thing

=A1-WEEKDAY(A1+3,3)

or

=A1-WEEKDAY(A1+2)+1

Personally I would avoid solutions using MOD like

=A1-MOD(A1+1,7)

because the result can change depending on date system, that will return a Thursday if you are using 1904 date system