"content":"<pre>\nDataFrame <code>products</code>\n+-------------+--------+\n| Column Name | Type |\n+-------------+--------+\n| name | object |\n| quantity | int |\n| price | int |\n+-------------+--------+\n</pre>\n\n<p>Write a solution to fill in the missing value as <code><strong>0</strong></code> in the <code>quantity</code> column.</p>\n\n<p>The result format is in the following example.</p>\n\n<p> </p>\n<pre>\n<strong class=\"example\">Example 1:</strong>\n<strong>Input:</strong>+-----------------+----------+-------+\n| name | quantity | price |\n+-----------------+----------+-------+\n| Wristwatch | None | 135 |\n| WirelessEarbuds | None | 821 |\n| GolfClubs | 779 | 9319 |\n| Printer | 849 | 3051 |\n+-----------------+----------+-------+\n<strong>Output:\n</strong>+-----------------+----------+-------+\n| name | quantity | price |\n+-----------------+----------+-------+\n| Wristwatch | 0 | 135 |\n| WirelessEarbuds | 0 | 821 |\n| GolfClubs | 779 | 9319 |\n| Printer | 849 | 3051 |\n+-----------------+----------+-------+\n<strong>Explanation:</strong> \nThe quantity for Wristwatch and WirelessEarbuds are filled by 0.</pre>\n",