in运算符：'in'运算符用于检查序列中是否存在值。如果在指定序列中找到变量，则求值为true，否则求值为false。

# Python program to illustrate

# Finding common member in list

# using 'in' operator

list1=[1,2,3,4,5]

list2=[6,7,8,9]

for item in list1:

if item in list2:

print("overlapping")

else:

print("not overlapping")

不使用in运算符的相同示例：

# Python program to illustrate

# Finding common member in list

# without using 'in' operator

# Define a function() that takes two lists

def overlapping(list1,list2):

c=0

d=0

for i in list1:

c+=1

for i in list2:

d+=1

for i in range(0,c):

for j in range(0,d):

if(list1[i]==list2[j]):

return 1

return 0

list1=[1,2,3,4,5]

list2=[6,7,8,9]

if(overlapping(list1,list2)):

print("overlapping")

else:

print("not overlapping")

输出：