Python's Calling function

Python's Calling function

Python has built in a lot of useful functions that we can call directly.

To invoke a function, you need to know the name and parameters of the function, such as an absolute function abs, which receives a parameter.

Documents can be viewed directly from the official website of Python: http://docs.python.org/2/library/functions.html#abs

You can also view the Help information for the ABS function on the interactive command line by helping (ABS).

Call the ABS function:

>>> ABS (100>>>) ABS ( -20) 20>>> abs (12.34) 12.34

When calling a function, if the number of arguments passed in is incorrect, the TypeError error is reported, and Python will explicitly tell you that ABS () has only 1 parameters, but gives two:

>>> ABS (1, 2) Traceback (most recent):  File "<stdin>", line 1, in <module>typeerror:abs () takes exactly one argument (2 given)

If the number of arguments passed in is correct, but the parameter type cannot be accepted by the function, the TypeError error is reported, and an error message is given: STR is the wrong parameter type:

>>> ABS (' a ') Traceback (most recent call last):  File "<stdin>", line 1, in <module>typeerror:bad Operand type for abs (): ' Str '

The comparison function cmp (x, y) requires two parameters, if x<y, returns 1, if x==y, returns 0, if X>y, returns 1:

>>> CMP (1, 2) -1>>> CMP (2, 1) 1>>> CMP (3, 3) 0

Python's built-in common functions also include data type conversion functions, such as the Int () function, which converts other data types to integers:

>>> Int (' 123 ') 123>>> Int (12.34) 12

The STR () function converts other types to str:

>>> STR (123) ' 123 ' >>> str (1.23) ' 1.23 '

Task

The sum () function takes a list as a parameter and returns the sum of all the elements of the list. Please calculate 1*1 + 2*2 + 3*3 + ... + 100*100.

? What's going on?

First, the list can be constructed with a while loop.

Reference code:

L = []x = 1while x <=:    l.append (x * x)    x = x + 1print sum (l)

Python's Calling function