我正在寻找一种方法来检查字符串是否定义了颜色，因为我的程序依赖于用户输入颜色，并且当他们输入错误的颜色时它会中断。我怎样才能做到这一点？以下是一些示例：
check_color("blue") > True
check_color("deep sky blue") > True
check_color("test") > False
check_color("#708090") > True
【问题讨论】：
这是使用matplotlib检查字符串是否定义颜色的方法：
>>> from matplotlib.colors import is_color_like
>>>
>>> is_color_like('red')
True
>>> is_color_like('re')
False
>>> is_color_like(0.5)
False
>>> is_color_like('0.5')
True
>>> is_color_like(None)
False
>>>
>>> matplotlib.colors.__file__
'/usr/lib/python2.7/site-packages/matplotlib/colors.py'
在 matplotlib.colors 模块的源代码中是这样写的：
该模块还提供了检查对象是否可以 解释为颜色 (:func:
is_color_like)，用于转换这样的对象 到 RGBA 元组 (:func:to_rgba) 或#rrggbb格式 (:func:to_hex)，以及(n, 4)的颜色序列 RGBA 数组 (:func:to_rgba_array)。缓存用于提高效率。
【讨论】：
一种可能的方法是使用colour 包。如果您没有安装它，请使用命令pip install colour。然后，您可以使用以下内容：
from colour import Color
def check_color(color):
try:
# Converting 'deep sky blue' to 'deepskyblue'
color = color.replace(" ", "")
Color(color)
# if everything goes fine then return True
return True
except ValueError: # The color code was not found
return False
check_color("blue")
check_color("deep sky blue")
check_color("test")
check_color("#708090")
【讨论】：
你应该使用这样的东西：
import re
VALID_COLORS = ['blue', 'red']
HEX_COLOR_REGEX = r'^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})$'
def is_hex_color(input_string):
regexp = re.compile(HEX_COLOR_REGEX)
if regexp.search(input_string):
return True
return False
def is_color(input_string):
for color in VALID_COLORS:
if color in input_string or is_hex_color(input_string):
return True
return False
【讨论】：
您可以使用外部颜色模块。用 pip 安装颜色模块：
pip install colour
那么你可以这样做：
>>> from colour import Color
>>> name = "blue"
>>> try:
Color(name.replace(" ",""))
print("Valid Color")
except:
print("Invalid color")
因为它在找不到颜色时引发异常。
【讨论】：
在 tkinter 中：widget.winfo_rgb('color')
【讨论】：
您好，我已经修改了一个 Pil 类来创建这个函数，它还可以进一步改进，但是它工作得很好，从来没有一个坏的惊喜。
import re
from PIL import Image
def isColor(color):
toColor = []
if isinstance(color, tuple):
for element in color:
toColor.append(isInt(element, 0))
if len(toColor) > 3:
toColor = [toColor[0], toColor[1], toColor[2]]
if len(toColor) == 3:
test = True
for element in toColor:
if element >= 0 and element < 256:
pass
else:
test = False
if test == True:
color = True
else:
color = False
else:
color = False
else:
color = getcolori(color, 'RGB')
return color
def isInt(value, remplacement=0):
if value != 0:
if isinstance(value, int):
pass
else:
if isinstance(value, str):
if value.isnumeric():
value = int(value)
else:
value = remplacement
else:
value = remplacement
else:
value = remplacement
return value
def getrgbi(color):
"""
Convert a color string to an RGB or RGBA tuple.
.. versionadded:: 1.1.4
:param color: A color string
:return: ``(red, green, blue[, alpha])``
"""
if len(color) > 100:
return False
color = color.lower()
rgb = colormap.get(color, None)
if rgb:
if isinstance(rgb, tuple):
return rgb
colormap[color] = rgb = getrgbi(rgb)
return True
# check for known string formats
if re.match("#[a-f0-9]{3}$", color):
return (int(color[1] * 2, 16), int(color[2] * 2, 16), int(color[3] * 2, 16))
if re.match("#[a-f0-9]{4}$", color):
return (
int(color[1] * 2, 16),
int(color[2] * 2, 16),
int(color[3] * 2, 16),
int(color[4] * 2, 16),
)
if re.match("#[a-f0-9]{6}$", color):
return (int(color[1:3], 16), int(color[3:5], 16), int(color[5:7], 16))
if re.match("#[a-f0-9]{8}$", color):
return (
int(color[1:3], 16),
int(color[3:5], 16),
int(color[5:7], 16),
int(color[7:9], 16),
)
m = re.match(r"rgb\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)$", color)
if m:
return (int(m.group(1)), int(m.group(2)), int(m.group(3)))
m = re.match(r"rgb\(\s*(\d+)%\s*,\s*(\d+)%\s*,\s*(\d+)%\s*\)$", color)
if m:
return (
int((int(m.group(1)) * 255) / 100.0 + 0.5),
int((int(m.group(2)) * 255) / 100.0 + 0.5),
int((int(m.group(3)) * 255) / 100.0 + 0.5),
)
m = re.match(
r"hsl\(\s*(\d+\.?\d*)\s*,\s*(\d+\.?\d*)%\s*,\s*(\d+\.?\d*)%\s*\)$", color
)
if m:
from colorsys import hls_to_rgb
rgb = hls_to_rgb(
float(m.group(1)) / 360.0,
float(m.group(3)) / 100.0,
float(m.group(2)) / 100.0,
)
return (
int(rgb[0] * 255 + 0.5),
int(rgb[1] * 255 + 0.5),
int(rgb[2] * 255 + 0.5),
)
m = re.match(
r"hs[bv]\(\s*(\d+\.?\d*)\s*,\s*(\d+\.?\d*)%\s*,\s*(\d+\.?\d*)%\s*\)$", color
)
if m:
from colorsys import hsv_to_rgb
rgb = hsv_to_rgb(
float(m.group(1)) / 360.0,
float(m.group(2)) / 100.0,
float(m.group(3)) / 100.0,
)
return (
int(rgb[0] * 255 + 0.5),
int(rgb[1] * 255 + 0.5),
int(rgb[2] * 255 + 0.5),
)
m = re.match(r"rgba\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)$", color)
if m:
return (int(m.group(1)), int(m.group(2)), int(m.group(3)), int(m.group(4)))
return False
def getcolori(color, mode):
"""
Same as :py:func:`~PIL.ImageColor.getrgb`, but converts the RGB value to a
greyscale value if the mode is not color or a palette image. If the string
cannot be parsed, this function raises a :py:exc:`ValueError` exception.
.. versionadded:: 1.1.4
:param color: A color string
:return: ``(graylevel [, alpha]) or (red, green, blue[, alpha])``
"""
# same as getrgb, but converts the result to the given mode
color, alpha = getrgbi(color), 255
if isinstance(color, bool):
return color
else:
if len(color) == 4:
color, alpha = color[0:3], color[3]
if Image.getmodebase(mode) == "L":
r, g, b = color
# ITU-R Recommendation 601-2 for nonlinear RGB
# scaled to 24 bits to match the convert's implementation.
color = (r * 19595 + g * 38470 + b * 7471 + 0x8000) >> 16
if mode[-1] == "A":
return True
else:
if mode[-1] == "A":
return True
return True
colormap = {
# X11 colour table from https://drafts.csswg.org/css-color-4/, with
# gray/grey spelling issues fixed. This is a superset of HTML 4.0
# colour names used in CSS 1.
"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",
"darkgrey": "#a9a9a9",
"darkgreen": "#006400",
"darkkhaki": "#bdb76b",
"darkmagenta": "#8b008b",
"darkolivegreen": "#556b2f",
"darkorange": "#ff8c00",
"darkorchid": "#9932cc",
"darkred": "#8b0000",
"darksalmon": "#e9967a",
"darkseagreen": "#8fbc8f",
"darkslateblue": "#483d8b",
"darkslategray": "#2f4f4f",
"darkslategrey": "#2f4f4f",
"darkturquoise": "#00ced1",
"darkviolet": "#9400d3",
"deeppink": "#ff1493",
"deepskyblue": "#00bfff",
"dimgray": "#696969",
"dimgrey": "#696969",
"dodgerblue": "#1e90ff",
"firebrick": "#b22222",
"floralwhite": "#fffaf0",
"forestgreen": "#228b22",
"fuchsia": "#ff00ff",
"gainsboro": "#dcdcdc",
"ghostwhite": "#f8f8ff",
"gold": "#ffd700",
"goldenrod": "#daa520",
"gray": "#808080",
"grey": "#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",
"lightgray": "#d3d3d3",
"lightgrey": "#d3d3d3",
"lightpink": "#ffb6c1",
"lightsalmon": "#ffa07a",
"lightseagreen": "#20b2aa",
"lightskyblue": "#87cefa",
"lightslategray": "#778899",
"lightslategrey": "#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",
"rebeccapurple": "#663399",
"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",
"slategrey": "#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",
}
#test
isColor('white') #True
isColor('bistolfy') #False
isColor('#fff') #True
isColor('hsl(45,0%,50%)') #True
isColor((255, 0, 0)) #True
isColor((255, 0, 0, 0))#True
【讨论】：