用python中的列表验证返回的列表？

Question

I have a function that returns me a single list. I'm trying to take what is returned and find if it exists in the list I already have. Am I missing another 'for' loop to iterate through cat_colors list? Or is the 'color' returned in a way that I can't match it in the list? Trying to understand it and if you have a better solution?

for cat in cat_names:
    color = Get_Color(cat)
    print cat_colors
    print color

    if color not in cat_colors:
        print "fail"
    else:
        print "pass"

output from print:

['brown', 'grey', 'white', 'black', 'red', 'orange', 'green', 'blue']
['brown']
fail

['brown', 'grey', 'white', 'black', 'red', 'orange', 'green', 'blue']
['grey']
fail

...

Answer 1

['brown'] isn't in ['brown', 'grey', 'white', 'black', 'red', 'orange', 'green', 'blue'] . The string 'brown' is.

You have two options here. If you know that color will always be a one-element list, you can do:

if color[0] in cat_colors:
   ...

If not, you could do:

if any(c in cat_colors for c in color):
   ...
   # or all(c in cat_colors for c in color) based on your needs

Answer 2

You should check for color not in cat_colors. Instead you are checking with cat not in cat_colors.

Change your code like this

for cat in cat_names:
    color = Get_Color(cat)
    print cat_colors
    print color

    if color[0] not in cat_colors:
        print "fail"
    else:
        print "pass"

Answer 3

Your Get_Color(cat) function must return a string
but it returns a list that's why you are not getting correct output

eg.
l1=['a','b','c','d']
l2=['a',['b'],['c','d']]

['b'] in l1
False
'b' in l1
True
['b'] in l2
True

['c'] in l2
False
['c','d'] in l2
True

Answer 4

And if you have cats with more than one color and you wanna know which colors of this perticular cat are in cat_colors:

def Get_Color(cat):
    if cat == 'whatevername1':
        color = ['brown', 'grey']
    elif cat == 'whatevername2':
        color = ['white', 'black', 'pink']
    elif cat == 'whatevername3':
        color = ['purple']
    return color
cat_names = ['whatevername1', 'whatevername2', 'whatevername3']
cat_colors = ['brown', 'grey', 'white', 'black', 'red', 'orange', 'green', 'blue']
print 'Valid colors:',cat_colors
for index,cat in enumerate(cat_names):
    color = Get_Color(cat)
    print 'Cat %s has colors:' %index,color
    valid_colors = set(cat_colors).intersection(color)
    if valid_colors:
        print 'Valid colors for cat %s are:' %index, valid_colors
    else:
        print "There are no valid colors for %s. Are you sure this is a real cat?"%index