PYTHON

python find in list

# There is several possible ways if "finding" things in lists.
'Checking if something is inside'
3 in [1, 2, 3] # => True
'Filtering a collection'
matches = [x for x in lst if fulfills_some_condition(x)]
matches = filter(fulfills_some_condition, lst)
matches = (x for x in lst if x > 6)
'Finding the first occurrence'
next(x for x in lst if ...)
next((x for x in lst if ...), [default value])
'Finding the location of an item'
[1,2,3].index(2) # => 1
[1,2,3,2].index(2) # => 1
[1,2,3].index(4) # => ValueError
[i for i,x in enumerate([1,2,3,2]) if x==2] # => [1, 3]

how to search for an item in a list in python

l = [1, 2, 3, 4, 5, 6, 7, 8, 9]
index_of_4 = l.index(4)
print(index_of_4)
##output:
## 3

find item in list

def findNumber(arr, k):
    if k in arr:
        print("YES")
    else:
        print("NO")

find an item in a list python

stuff = ['book', 89, 5.3, True, [1, 2, 3], (4, 3, 2), {'dic': 1}]
print('book' in stuff)          # Output: True
print('books' in stuff)         # Output: False
# Remember it is case-sensitive
print('Book' in stuff)          # Output: False
print([1,2,3] in stuff)         # Output: True
print([1,2,3] not in stuff)     # Output: False

python search list by value

[1,2,3].index(2) # => 1
[1,2,3].index(4) # => ValueError