python到php代码转换

Question

I have to translate two Python functions into PHP. The first one is:

def listspaces(string):
        return [i -1 for i in range(len(string)) if string.startswith(' ', i-1)]

I am assuming that this will check for space in provided string and return True when first occurrence of space is found, is this correct ?

What is i-1 here ? is it -1 ?

In PHP we use [] for arrays . Here we are [] with return, will this function return true or false or array of locations of spaces ?

Second function is

def trimcopy(copy, spaces, length=350):

    try:
        if len(copy) < length:
            return copy
        else:
            loc = 0
            for space in spaces:
                if space < length:
                    loc = space
                else:
                    return copy[:loc]
    except :
        return None

Whats for space in spaces: here and whats is this return copy[:loc]

Answer 1

You may notice that the first function could also have been written as

def listspaces(str):
    return [i for i, c in enumerate(str) if c==' ']

That version has the following straightforward conversion to PHP:

function listspaces($str) {
    $spaces = array();

    foreach (str_split($str) as $i => $chr)
        if ($chr == ' ') $spaces[] = $i;

    return $spaces;
}

As for the other function, this seems to do the same thing in very nearly the same idiom:

function trimcopy($copy, $spaces, $length=350) {
    if (strlen($copy) < $length) {
        return $copy;
    } else {
        foreach ($spaces as $space) {
            if ($space < $length) {
                $loc = $space;
            } else {
                return substr($copy, 0, $loc);
            }
        }
    }
}

As others have pointed out, the intent of both of these functions could probably be better expressed by using wordwrap.