Subtracting time Duration from time in Go

Question

I have a time Time value obtained from time Now   and I want to get another time which is exactly 1 month ago    I know subtracting is possible with time Sub    which wants another time Time   but that will result in a time Duration and I need it the other way around

User · Answer

You can negate a time Duration   then    now Add - dur    You can even compare a time Duration against 0   if dur  gt  0       dur   - dur    then    now Add dur    You can see a working example at http   play golang org p ml7svlL4eW

User · Answer

Try AddDate   package main  import        fmt       time     func main         now    time Now        fmt Println  now    now       then    now AddDate 0  -1  0       fmt Println  then    then      Produces   now  2009-11-10 23 00 00  0000 UTC then  2009-10-10 23 00 00  0000 UTC   Playground  http   play golang org p QChq02kisT

User · Answer

In response to Thomas Browne s comment  because lnmx s answer only works for subtracting a date  here is a modification of his code that works for subtracting time from a time Time type   package main  import        fmt       time     func main         now    time Now        fmt Println  now    now       count    10     then    now Add time Duration -count    time Minute         if we had fix number of units to subtract  we can use following line instead fo above 2 lines  It does type convertion automatically         then    now Add -10   time Minute      fmt Println  10 minutes ago    then      Produces   now  2009-11-10 23 00 00  0000 UTC 10 minutes ago  2009-11-10 22 50 00  0000 UTC   Not to mention  you can also use time Hour or time Second instead of time Minute as per your needs   Playground  https   play golang org p DzzH4SA3izp

User · Answer

There s time ParseDuration which will happily accept negative durations  as per manual  Otherwise put  there s no need to negate a duration where you can get an exact duration in the first place   E g  when you need to substract an hour and a half  you can do that like so   package main  import        fmt       time     func main         now    time Now        fmt Println  now    now       duration       time ParseDuration  -1 5h        then    now Add duration       fmt Println  then    then      https   play golang org p 63p-T9uFcZo

[go] Subtracting time.Duration from time in Go

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