I was looking for a way to add a suffix to jointchain in Maya. The jointchain has specific naming so I create a list with the names they need to be. The first chain has "_1" as suffix, result:

R_Clavicle_1|R_UpperArm_1|R_UnderArm_1|R_Wrist_1

When I create the second this is the result:

R_Clavicle_2|R_UpperArm_1|R_UnderArm_1|R_Wrist_1

The code:

DRClavPos = cmds.xform ('DRClavicle', q=True, ws=True, t=True)
DRUpArmPos = cmds.xform ('DRUpperArm', q=True, ws=True, t=True) 
DRUnArmPos = cmds.xform ('DRUnderArm', q=True, ws=True, t=True) 
DRWristPos = cmds.xform ('DRWrist', q=True, ws=True, t=True), cmds.xform('DRWrist', q=True, os=True, ro=True)

suffix = 1
jntsA = cmds.ls(type="joint", long=True)
while True:
    jntname = ["R_Clavicle_"+str(suffix),"R_UpperArm_"+str(suffix),"R_UnderArm_"+str(suffix),"R_Wrist_"+str(suffix)]
    if jntname not in jntsA:
        cmds.select (d=True)  
        cmds.joint ( p=(DRClavPos))
        cmds.joint ( p=(DRUpArmPos))
        cmds.joint ( 'joint1', e=True, zso=True, oj='xyz', radius=0.5, n=jntname[0])
        cmds.joint ( p=(DRUnArmPos))
        cmds.joint ( 'joint2', e=True, zso=True, oj='xyz', radius=0.5,  n=jntname[1])
        cmds.joint ( p=(DRWristPos[0]))
        cmds.joint ( 'joint3', e=True, zso=True, oj='xyz', radius=0.5,  n=jntname[2])
        cmds.rename ('joint4', jntname[3])
        cmds.select ( cl=True)
        break
    else:
        suffix + 1

I tried adding +1 in jntname which resulted in a good second chain but the third chain had "_2" after R_Clavicle_3

The code, in my eyes should work. Can anybody point me in the correct direction :)