for vs. foreach

proc a {list1} {
    for {set i 0} {$i < [llength $list1]} {incr i} {
	lappend a [lindex $list1 $i]
    }
}

proc b {list1} {
    foreach item $list1 {
	lappend a $item
    }
}

for {set i 0} {$i < 100000} {incr i} {
    lappend list1 $i
}

puts [time {a $list1} 10]
puts [time {b $list1} 10]