sscanf的：获得第一和最后一个令牌在一个字符串 [英] sscanf: get first and last token in a string

问题描述

是否有可能通过使用sscanf会得到的第一个标记，然后跳过一些代币，然后拿到最后一个？

Is it possible by using sscanf to get the first token then skip some tokens and then get the last one?

例如，/ bin中的输出/ PS -fu1000

For example, the output of /bin/ps -fu1000

  cm  2249  1548   0   0:00.00 ttys001    0:00.01 man sscanf

我曾尝试：

sscanf(line, "%s %[^\n]", user, cmd);

结果应该是：

user = "cm";
cmd = "man sscanf":

不过，这是行不通的。

But it does not work.

推荐答案

是的，但它的丑陋，不能正确错误检查。

Yes, but it's ugly and can't be error checked properly.

/* assuming `user` and `cmd` are character arrays defined with 42 bytes */
if (sscanf(line, "%41s%*s%*s%*s%*s%*s%*s %41[^\n]", user, cmd) != 2) {
    /* handle error */
} else {
    /* hopefully ok */
}

您可以取代一些％* S 与％* D 。在 * 表示，该项目被解析，但不指定任何地方（它被忽略）。

You can replace some of the %*s with %*d. The * means that the item is parsed but not assigned anywhere (it is ignored).

在声明中，也有厘米和人sscanf的在你的例子。

In the statement, there are 6 ignored items corresponding to the items between "cm" and "man sscanf" in your example.

另外请注意我限制了输入41个字符的scanf函数本身。确保你不要在外面对象写。

Also note I limited the input to 41 characters in the scanf itself. Make sure you do not write outside the objects.

编辑：我最后一次转换之前加一个空格，因为不像％S 或％d个转换， ％[转换不会跳过前导空白。

I added a space before the last conversion because, unlike %s or %d conversions, the %[ conversion does not skip leading whitespace.

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