如何在Python / Spyder 2.7中比较字符串与列表列表

Question

I have a list:

myList = [['first'],['second'], ['third']]

and a comparison string, myStr = 'first'

I want to return True if myStr exists in myList, else False .

Answer 1

Just for the simple example you have shown, run

[myStr] in myList

But you should probably make myList equal a flat list if each sublist contains only one item - myList = ['first', 'second', 'third']

Then you only need

myStr in myList

Answer 2

In Python 2.7:

str = "first"
array = [["first"], ["second"], ...]
def isInArray(string, array):
    for subarray in array:
        for element in subarray:
            if element == string:
                return True
    return False
print isInArray(str, array)

Anyway, the array makes no sense: if each subarray has only one element, you should make it easier:

array = ["first", "second", ...]

Answer 3

You need to iterate over the list with the for loop just once so that you can access the sublists

myStr = 'first'
myList = [['first'],['second'], ['third']]

def str_in_list_of_lists(myStr, myList):
    for i in myList:
        if myStr in i:
            return True
    return False
print str_in_list_of_lists(myStr, myList)

Example in Python 2.7:

food = [["apples", "prunes", "peaches"], ["tea", "coffee", "milk"], ["biscuits", "bread", "chips"]]

*You can try different strings here to check True/False values*

find = raw_input("What do you want in food?")

def str_in_list_of_lists(a, b):
    for i in food:
        if find in i:
            return True
    return False
print str_in_list_of_lists(find, food)