Python : What is the purpose of a colon in an if statement?

Question

I have this piece of python code below.

def m(list):
    v = list[0]
    for e in list:
        if v < e:
            v = e
        return v

values = [[3, 4,         


        

Answer 1

if v < e: v = e

can be read: "If v is less than e, make v the value of e."

As above you should put a new line to make it read easier:

if v < e:
    v = e

Answer 2

It's called a colon in english, not a double colon or double comma.

I urge you to read a basic Python introduction.

if v < e: v = e

Is the same as:

if v < e:
    v = e

Answer 3

In [8]: v = 1
In [9]: e = 2
In [10]: if v < e: v = e
In [11]: v
Out[11]: 2
In [12]: e
Out[12]: 2

is same as:

In [13]: v = 1
In [14]: e = 2
In [15]: if v < e:  # if True execute next statement 
   ....:     v = e
   ....:     
In [16]: v
Out[16]: 2
In [17]: e
Out[17]: 2

Answer 4

Another way to write that code is like this, just for learning purposes:

    def max_nest_list(lst):
        max_numbers = []
        for sub_list in lst:
            max_num = sub_list[0]
            for num in sub_list[1:]:
                if num > max_num:
                     max_num = num
            max_numbers.append(max_num)
        return max_numbers

    values = [[3, 4, 5, 1], [33, 6, 1, 2]]
    for item in max_nest_list(values):
        print(item, end = " ")

    #Output
    5 33

Or even more concise:

    def max_nest_list2(lst):
        return [max(i) for i in lst]

    values = [[3, 4, 5, 1], [33, 6, 1, 2]]
    for item in max_nest_list(values):
        print(item, end = " ")