我有一组对象var玩家:[domain]玩家和我想以相反的顺序迭代对象。像
这样的东西这有效
for p in Players by {
writeln(p.name);
writeln("I was the %i st player added".format(p.pid)") // pid corresponds to domain index.
p.shoeSize = 1.5*p.shoeSize
}
但是!
// poops
for p in Players by -1 {
writeln(p.name);
writeln("I was the %i -to-last player added".format(p.pid)") // pid corresponds to domain index.
p.shoeSize = 1.5*p.shoeSize
}
我想确保鞋子尺寸更新。
== UPDATE ==
一些额外的信息/规范,以兑现@ bencray的请求
class Player {
var name: string,
position: string,
pid: int,
shoeSize: int;
}
var playerDom = {1..0},
players: [playerDom] Player;
writeln("I have %i players".format(playerDom.size));
// Now add some players
// Better way to increase as I go along?
playerDom = {1..playerDom.size+1};
players[playerDom.size] = new Player(name="Gretsky", position="Center", shoeSize=10, pid=playerDom.size);
writeln("I have %i players".format(playerDom.size));
playerDom = {1..playerDom.size+1};
players[playerDom.size] = new Player(name="Blake", position="Defenseman", shoeSize=12, pid=playerDom.size);
writeln("I have %i players".format(playerDom.size));
for p in players {
writeln("Player %i has shoeSize %i".format(p.pid, p.shoeSize));
p.shoeSize += 1;
}
for p in players {
writeln("Player NOW %i has shoeSize %i".format(p.pid, p.shoeSize));
}
// poops during compilation
// domobj.chpl:31: error: the first argument of the 'by' operator is not a range
for p in players by -1 {
writeln("Player NOW %i has shoeSize %i".format(p.pid, p.shoeSize));
}
答案 0 :(得分:1)
范围操作by
对您希望的数组不起作用。相反,我们留下了稍微不那么优雅的迭代索引形式,如下所示:
for i in players.domain by -1 {
writeln("Player NOW %i has shoeSize %i".format(players[i].pid, players[i].shoeSize));
}
下面是你的更大的代码块以及其他一些清理:
var playerDom = {1..0},
players: [playerDom] Player;
writeln("I have %i players".format(playerDom.size));
players.push_back(new Player(name="Gretsky", position="Center", shoeSize=10, pid=players.size+1));
writeln("I have %i players".format(playerDom.size));
players.push_back(new Player(name="Blake", position="Defenseman", shoeSize=12, pid=players.size+1));
writeln("I have %i players".format(playerDom.size));
for p in players {
writeln("Player %i has shoeSize %i".format(p.pid, p.shoeSize));
p.shoeSize += 1;
}
for p in players {
writeln("Player NOW %i has shoeSize %i".format(p.pid, p.shoeSize));
}
for i in players.domain by -1 {
ref p = players[i];
writeln("Player NOW %i has shoeSize %i".format(p.pid, p.shoeSize));
}
class Player {
var name: string,
position: string,
pid: int,
shoeSize: int;
}