[python] How to compare two lists in python?

How to compare two lists in python?

date = "Thu Sep 16 13:14:15 CDT 2010" 
sdate = "Thu Sep 16 14:14:15 CDT 2010" 
dateArr = [] dateArr = date.split() 
sdateArr = [] sdateArr = sdate.split() 

Now I want to compare these two lists. I guess split returns a list. We can do simple comparision in Java like dateArr[i] == sdateArr[i], but how can we do it in Python?

If you mean lists, try ==:

l1 = [1,2,3]
l2 = [1,2,3,4]

l1 == l2 # False

If you mean array:

l1 = array('l', [1, 2, 3])
l2 = array('d', [1.0, 2.0, 3.0])
l1 == l2 # True
l2 = array('d', [1.0, 2.0, 3.0, 4.0])
l1 == l2 # False

If you want to compare strings (per your comment):

date_string  = u'Thu Sep 16 13:14:15 CDT 2010'
date_string2 = u'Thu Sep 16 14:14:15 CDT 2010'
date_string == date_string2 # False

a = ['a1','b2','c3']
b = ['a1','b2','c3']
c = ['b2','a1','c3']

# if you care about order
a == b # True
a == c # False

# if you don't care about order AND duplicates
set(a) == set(b) # True
set(a) == set(c) # True

By casting a, b and c as a set, you remove duplicates and order doesn't count. Comparing sets is also much faster and more efficient than comparing lists.

Given the code you provided in comments, I assume you want to do this:

>>> dateList = "Thu Sep 16 13:14:15 CDT 2010".split()
>>> sdateList = "Thu Sep 16 14:14:15 CDT 2010".split()
>>> dateList == sdataList
false

The split-method of the string returns a list. A list in Python is very different from an array. == in this case does an element-wise comparison of the two lists and returns if all their elements are equal and the number and order of the elements is the same. Read the documentation.

From your post I gather that you want to compare dates, not arrays. If this is the case, then use the appropriate object: a datetime object.

Please check the documentation for the datetime module. Dates are a tough cookie. Use reliable algorithms.

for i in arr1:
    if i in arr2:
        return 1
    return  0
arr1=[1,2,5]
arr2=[2,4,15]
q=checkarrayequalornot(arr1,arr2)
print(q)
>>0