How do I check if a list (list_1) contains the same elements located in same order of another list (list_2)?

Question

I have 2 lists: list_1 and list_2.

list_1: ['one', 'took', 'a', 'walk', 'yeah', 'i', 'watched', 'the', 'world', 'happens', 'now']

I’ve

list_2: ['yeah', 'i', 'watched', 'the', 'world']

and

list_3: ['yeah', 'one', 'took', 'a', 'world', 'walk', 'i', 'the', 'happens', 'now', 'watched']

I want to check if the elements in list_2 are present in list_1 in the same order, in this case

['yeah', 'i', 'watched', 'the', 'world']

regardless of the starting and ending position in the list_1.

However, when if I compare list_3 vs list_2, although all the elements from list_2 are present in list_3, they are ordered differently.

In the first case (list_1 vs list_2), the answer would be True.
In the second case (list_3 vs list_2), the answer would be False.

Asked By: user20716077

||

Source

Answer 1

Here is the code. If you enter 2 list in the function, the function will check if all the elements in second list are inside first list with same order in both list.

list_1= ['one', 'took', 'a', 'walk', 'yeah', 'i', 'watched', 'the', 'world', 'happens', 'now']
list_2= ['yeah', 'i', 'watched', 'the', 'world']
list_3= ['yeah', 'one', 'took', 'a', 'world', 'walk', 'i', 'the', 'happens', 'now', 'watched']
def check(ref_list, check_list):
    matching=0
    for i in range(len(ref_list)):
        if check_list[0]==ref_list[i] and check_list[1]==ref_list[i+1]:
            for j in range(len(check_list)):
                if check_list[j]==ref_list[i+j]:
                    matching=1
                else:
                    matching=0
                if j==len(check_list)-1:
                    if matching==1:
                        print("checking list Matched with reference")
                        return 0
                    else:
                        print("Didn't match")
                        return 0
    if matching==0:
        print("Didn't match")
        return 0
check(list_1,list_2)

Answered By: Nissan Apollo

Answer 2

Method:
start at beginning of list1
loop:
find position of word of list2 in remaining of list1.
Return False if not in list1.

def match( list2, list1):
  i0 = 0 # start point in list1
  for i2 in range( len( list2)):
    for i1 in range( i0, len( list1)):
      if list1[i1]==list2[i2]:
        i0 = i1 # next search will start here
        break
    else:
      return False # not found
  return True # match

list1= ['one', 'took', 'a', 'walk', 'yeah', 'i', 'watched', 'the', 'world', 'happens', 'now']
list2= ['yeah', 'i', 'watched', 'the', 'world']
list3= ['yeah', 'one', 'took', 'a', 'world', 'walk', 'i', 'the', 'happens', 'now', 'watched']

match( list2, list1) # return True
match( list2, list3) # return False

Answered By: user3435121

How do I check if a list (list_1) contains the same elements located in same order of another list (list_2)?

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