print("***** abs *****")
x = -3
y = abs(x)

# abs: Absolute value of a numeric type
print(y)

# ---------------- OUTPUT ----------------
# 3


print("***** multiply *****")
# True will be repeated 5 times
x = [True] * 5
print(x)

# to check all items are True
print(all(x))

# append False to array and check again
x.append(False)
print(x)
print(all(x))

# check if any is True
print(any(x))

# ---------------- OUTPUT ----------------
# ***** multiply *****
# [True, True, True, True, True]
# True
# [True, True, True, True, True, False]
# False
# True


print("***** enumerate *****")
# used to loop over a list with a counter

for pos, letter in enumerate("python"):
    print(str(pos) + "=>" + letter)

# ---------------- OUTPUT ----------------
# ***** enumerate *****
# 0=>p
# 1=>y
# 2=>t
# 3=>h
# 4=>o
# 5=>n


print("***** eval *****")
# eval interprets a string as code => allows to run a string as python code
x = 1
print(eval("x + 3"))

# ---------------- OUTPUT ----------------
# ***** eval *****
# 4


print("***** filter array *****")
ages = [6, 8, 12, 19, 7, 39, 24, 65]

def older(x):
    return x > 19

for item in filter(older, ages):
    print(item)

# ---------------- OUTPUT ----------------
# ***** filter array *****
# 39
# 24
# 65


print("***** map *****")
# use map to apply function to each item in a list

def square(x):
    return x * x

for item in map(square, range(1,10)):
    print("square %d" % item)

# ---------------- OUTPUT ----------------
# ***** map *****
# square 1
# square 4
# square 9
# square 16
# square 25
# square 36
# square 49
# square 64
# square 81


print("***** pow *****")
# power of a number
x = 3
y = 4
print(pow(x, y))

# ---------------- OUTPUT ----------------
# ***** pow *****
# 81


print("***** zip *****")
# to create tuples from 2 arrays

x = [1, 2, 3, 4]
y = ["a", "b", "c", "d"]
z = zip(x, y)

for a in z:
    print(a)

# combine zip and dict to create dictionary from 2 arrays
d = dict(zip(x,y))
print(d)

# ---------------- OUTPUT ----------------
# ***** zip *****
# (1, 'a')
# (2, 'b')
# (3, 'c')
# (4, 'd')
# {1: 'a', 2: 'b', 3: 'c', 4: 'd'}