# Python's for statement iterates over the items of any sequence or iterable (list,tuple,string,dictionary(mapping))

# in the order that they appear in the sequence.

''' For using Range'''

# In a nutshell, range() generates successive Values .

# which is generally used TO ITERATE over with for loops.

# There's many use cases.

# Often you will want to use this when you want to perform an action X number of times,

# where you may or may not care about the index.

# Other times you may want to iterate over a list (or another iterable object),

# while being able to have the index available. Using membership functionality.

# All parameters must be integers.

# All parameters can be positive or negative.

# If we are giving a negative parameter, We have to use a negative step too.

'''range(stop)'''

for element in range(5): # last integer is not included.

print(element)

print("\n")

# ------------------------------------------------------------------------

''' range([start], stop)'''

for element in range(3,8):

print(element)

print("\n")

#---------------------------------------------------------------------------

'''range([start], stop, [step])'''

for element in range(3,10,2):

print(element)

print("\n")

# Negative step

for element in range(10,3,-2):

print(element)

print("\n")

for element in range(3,10,-2):

print(element) # Won't work but won't show any error. Just that there will be

# no iteration happening. Since wrong collection given.

#--------------------------------------------------------------------------

my_list = [1,2,3,4]

for i in range(len(my_list)): # len will be 4.

print(my_list[i])

print("\n")

# Python 3.x, the range() function got its own type

a = range(5)

print(a)

print(type(a)) # class = range

#---------------------------------------------------------------------

num = 10

print(num)

for num in range(5):

print(num)

print(num)

# num defined out of for's scope is used within too.

# num is updated to 4 since num has only one scope (main scope)

#--------------------------------------------------------------------------

print("\n")

''' Range checking the variable only for 1st iteration'''

x = 4

for j in range(x):

for i in range(x):

print(i)

x = 2

print("\n")

# When we first enter the outer loop x is 4.

# Now for tht loop x will not change

# when we enter the innermost loop, x is set to 4.

# But when we exit x has now a value of 2.

# Remember - range generates all the values at the very first iteration.

# Therefore every time you go through the outer loop after 1st iteration,

# range won't check x.

# But when you go to the innermost loop. It is running afresh.

# Therefore x is set to 2 at 1st iteration.

#------------------------------------------------------------------------

'''Let s be a string that contains a sequence of decimal numbers

separated by commas, e.g., s = '1.23,2.4,3.123'. Write a program that prints

the sum of the numbers in s.'''

total = 0.0

my_str = input("Enter decimal numbers separated with comma : ")

my_list = my_str.split(",") # I splitted the numbers and stored them as string

# in a list.

for each in my_list:

total = total + float(each) # casted each element of list to float

print("total sum is",total) # Found the total.