how do we read strumming patterns?

for eg i found these strumming patterns 4 roobaroo

ddu ddu dudu
D_DUUDUD

i understand what u and d mean but wais with those space and underscore?

or
Roobaroo ..RDB

like
1....^^v^^v^V==== for A chord
2....V--^v^v^===== for D chord

how do i play this?

or

1 1 12 12 12

wat r 1 and 2

kindly help.......

 

d stands for downstroke and u stands for upstroke

 

i no that but wat about the others??

 

those others are either brakes (where u dont let the chord ring) or a gap (time)......

 

these stands for

D,^,1 --------> Down strum

U,v,2 ----------> Up strum

 

I think _ stands for a pause