使用Python编写css21_names_to_hex()函数实现CSS21颜色名称转换为十六进制表示方式

函数名称：css21_names_to_hex()

函数功能：将CSS21颜色名称转换为十六进制表示方式。

函数输入参数：

- color_names: 一个包含CSS21颜色名称的列表

函数返回值：

- 一个包含对应的十六进制表示方式的颜色代码的列表

函数实现过程：

1. 创建一个空列表hex_colors，用于存储转换后的颜色代码。

2. 对于color_names列表中的每个颜色名称，执行以下操作：

- 如果颜色名称是CSS21规范中已定义的颜色名称，则将其对应的十六进制颜色代码添加到hex_colors列表中。

- 否则，将该颜色名称视为无效，将"Invalid"字符串添加到hex_colors列表中。

3. 返回hex_colors列表作为函数的结果。

以下是css21_names_to_hex()函数的Python实现代码：

def css21_names_to_hex(color_names):
    hex_colors = []
    css21_colors = {
        "aliceblue": "#f0f8ff", "antiquewhite": "#faebd7", "aqua": "#00ffff", "aquamarine": "#7fffd4",
        "azure": "#f0ffff", "beige": "#f5f5dc", "bisque": "#ffe4c4", "black": "#000000",
        "blanchedalmond": "#ffebcd", "blue": "#0000ff", "blueviolet": "#8a2be2", "brown": "#a52a2a",
        "burlywood": "#deb887", "cadetblue": "#5f9ea0", "chartreuse": "#7fff00", "chocolate": "#d2691e",
        "coral": "#ff7f50", "cornflowerblue": "#6495ed", "cornsilk": "#fff8dc", "crimson": "#dc143c",
        "cyan": "#00ffff", "darkblue": "#00008b", "darkcyan": "#008b8b", "darkgoldenrod": "#b8860b",
        "darkgray": "#a9a9a9", "darkgreen": "#006400", "darkkhaki": "#bdb76b", "darkmagenta": "#8b008b",
        "darkolivegreen": "#556b2f", "darkorange": "#ff8c00", "darkorchid": "#9932cc", "darkred": "#8b0000",
        "darksalmon": "#e9967a", "darkseagreen": "#8fbc8f", "darkslateblue": "#483d8b", "darkslategray": "#2f4f4f",
        "darkturquoise": "#00ced1", "darkviolet": "#9400d3", "deeppink": "#ff1493", "deepskyblue": "#00bfff",
        "dimgray": "#696969", "dodgerblue": "#1e90ff", "firebrick": "#b22222", "floralwhite": "#fffaf0",
        "forestgreen": "#228b22", "fuchsia": "#ff00ff", "gainsboro": "#dcdcdc", "ghostwhite": "#f8f8ff",
        "gold": "#ffd700", "goldenrod": "#daa520", "gray": "#808080", "green": "#008000",
        "greenyellow": "#adff2f", "honeydew": "#f0fff0", "hotpink": "#ff69b4", "indianred": "#cd5c5c",
        "indigo": "#4b0082", "ivory": "#fffff0", "khaki": "#f0e68c", "lavender": "#e6e6fa",
        "lavenderblush": "#fff0f5", "lawngreen": "#7cfc00", "lemonchiffon": "#fffacd", "lightblue": "#add8e6",
        "lightcoral": "#f08080", "lightcyan": "#e0ffff", "lightgoldenrodyellow": "#fafad2", "lightgreen": "#90ee90",
        "lightgrey": "#d3d3d3", "lightpink": "#ffb6c1", "lightsalmon": "#ffa07a", "lightseagreen": "#20b2aa",
        "lightskyblue": "#87cefa", "lightslategray": "#778899", "lightsteelblue": "#b0c4de", "lightyellow": "#ffffe0",
        "lime": "#00ff00", "limegreen": "#32cd32", "linen": "#faf0e6", "magenta": "#ff00ff",
        "maroon": "#800000", "mediumaquamarine": "#66cdaa", "mediumblue": "#0000cd", "mediumorchid": "#ba55d3",
        "mediumpurple": "#9370db", "mediumseagreen": "#3cb371", "mediumslateblue": "#7b68ee", "mediumspringgreen": "#00fa9a",
        "mediumturquoise": "#48d1cc", "mediumvioletred": "#c71585", "midnightblue": "#191970", "mintcream": "#f5fffa",
        "mistyrose": "#ffe4e1", "moccasin": "#ffe4b5", "navajowhite": "#ffdead", "navy": "#000080",
        "oldlace": "#fdf5e6", "olive": "#808000", "olivedrab": "#6b8e23", "orange": "#ffa500",
        "orangered": "#ff4500", "orchid": "#da70d6", "palegoldenrod": "#eee8aa", "palegreen": "#98fb98",
        "paleturquoise": "#afeeee", "palevioletred": "#db7093", "papayawhip": "#ffefd5", "peachpuff": "#ffdab9",
        "peru": "#cd853f", "pink": "#ffc0cb", "plum": "#dda0dd", "powderblue": "#b0e0e6",
        "purple": "#800080", "red": "#ff0000", "rosybrown": "#bc8f8f", "royalblue": "#4169e1",
        "saddlebrown": "#8b4513", "salmon": "#fa8072", "sandybrown": "#f4a460", "seagreen": "#2e8b57",
        "seashell": "#fff5ee", "sienna": "#a0522d", "silver": "#c0c0c0", "skyblue": "#87ceeb",
        "slateblue": "#6a5acd", "slategray": "#708090", "snow": "#fffafa", "springgreen": "#00ff7f",
        "steelblue": "#4682b4", "tan": "#d2b48c", "teal": "#008080", "thistle": "#d8bfd8",
        "tomato": "#ff6347", "turquoise": "#40e0d0", "violet": "#ee82ee", "wheat": "#f5deb3",
        "white": "#ffffff", "whitesmoke": "#f5f5f5", "yellow": "#ffff00", "yellowgreen": "#9acd32"
    }

    for color_name in color_names:
        if color_name.lower() in css21_colors:
            hex_colors.append(css21_colors[color_name.lower()])
        else:
            hex_colors.append("Invalid")

    return hex_colors

以下是一个使用例子：

color_names = ["red", "blue", "green", "purple", "pink", "orange", "yellow", "invalid"]
hex_colors = css21_names_to_hex(color_names)

for i in range(len(color_names)):
    print(f"{color_names[i]}: {hex_colors[i]}")

输出结果：

red: #ff0000
blue: #0000ff
green: #008000
purple: #800080
pink: #ffc0cb
orange: #ffa500
yellow: #ffff00
invalid: Invalid

注意：如果颜色名称不是CSS21颜色规范中已定义的颜色名称，将返回"Invalid"字符串。