tcl - 使用值被 {} 包围的列表模式

Question

我的数据为 {} {abc}、{abc} {} 或 {abc} {def}，并且我想用两个变量来捕获它。我尝试过:

foreach {fname} <program to get values> {
    set dfrom [lindex $fname 1]
    set rname [lindex $fname 2]
    print "fname- $fname"
    print "dfrom- $dfrom"
    print "rname- $rname"
}

但是，{} 未获取索引。

Answer 1

来自manual about lindex ，强调我的:

When presented with a single index, the lindex command treats list as a Tcl list and returns the index'th element from it (0 refers to the first element of the list)

所以你必须使用类似这样的东西:

foreach {fname} <program to get values> {
    set dfrom [lindex $fname 0]
    set rname [lindex $fname 1]
    print "fname- $fname"
    print "dfrom- $dfrom"
    print "rname- $rname"
}

如果您使用的是 Tcl 8.5 或更高版本，则可以使用 lassign :

foreach {fname} <program to get values> {
    lassign $fname dfrom rname
    print "fname- $fname"
    print "dfrom- $dfrom"
    print "rname- $rname"
}