Python：在ForLoop内部调用函数

Question

I'm supposed to answer specific questions given 2 different lists, a list of numbers and a list of words, using functions to answer said questions.

I currently am running into two problems. Regarding the numbers list, I have to find the length of the list, even numbers, which numbers are greater than 100, and add 30 to each number in the list and print the answers out.

First, I have these functions to answer those questions:

def print_list(*args):
    for item in args:
        print item

def lenList(listName):
    return len(listName)

def numEven(num):
    if num%2==0:
        print "%d is even." % num

def moreThan100(num):
    if num>100:
        print "%d is greater than 100." % num

def adding30(num):
    print "If you add 30 to %d, you get: %d" % (num,num+30)

Then I have these functions nested inside one function:

def leWork():
    numbers=[56,3,9,1002,33,66,789,9001,999,222,82,71,5,3]

    numLength=lenList(numbers)
    print "The length of the numbers[] is %d" % numLength

    for num in numbers:
        numEven(num), 
        moreThan100(num), 
        adding30(num)
leWork()

My problem is when running the code, I don't get an organized list stating the even numbers first,then the numbers > 100, and then the returns after adding 30. They are just scattered like this:

The length of the numbers[] is 14
56 is even.
If you add 30 to 56, you get: 86
If you add 30 to 3, you get: 33
If you add 30 to 9, you get: 39
1002 is even.
1002 is greater than 100.
If you add 30 to 1002, you get: 1032
If you add 30 to 33, you get: 63
66 is even.
If you add 30 to 66, you get: 96
789 is greater than 100.
If you add 30 to 789, you get: 819
9001 is greater than 100.
If you add 30 to 9001, you get: 9031
999 is greater than 100.
If you add 30 to 999, you get: 1029
222 is even.
222 is greater than 100.
If you add 30 to 222, you get: 252
82 is even.
If you add 30 to 82, you get: 112
If you add 30 to 71, you get: 101
If you add 30 to 5, you get: 35
If you add 30 to 3, you get: 33

How exactly would I go about making them in a more organized list?

Answer 1

If you want to first state all the even numbers, then state all the numbers > 100, etc., the easiest solution is to first loop and find all the even numbers, then loop and find the big numbers, etc. Like this:

for num in numbers:
    numEven(num), 
for num in numbers:
    moreThan100(num), 
for num in numbers:
    adding30(num)

However, a much better solution would be to change your functions to return a value instead of just printing something, and store those return values, and then you'd be able to print them out any way you want—say, by using that print_list function you went out of your way to write. For example:

def numEven(num):
    return num%2==0

def moreThan100(num):
    return num>100

def adding30(num):
    return num+30

evens, bigs, plus30s = [], [], []
for num in numbers:
    if numEven(num):
        evens.append("%d is even." % num)
    if moreThan100(num):
        bigs.append("%d is greater than 100." % num)
    plus30 = adding30(num)
    plus30s.append("If you add 30 to %d, you get: %d" % (num,plus30))

print_list(*events)
print_list(*bigs)
print_list(*plus30s)

Answer 2

It's how you are iterating your number, to just "fix" the error:

for num in numbers:
    numEven(num)

for num in numbers:
    moreThan100(num)

for num in numbers:
    adding30(num)

Answer 3

You are iterating over the list of numbers, and for each number you are calling all your functions. To obtain what you want you may want consider doing

numbers=[56,3,9,1002,33,66,789,9001,999,222,82,71,5,3]
func_list = [numEven,moreThan100, adding30]

for f in func_list:
    map(f,numbers)

Answer 4

I would not put any print statements in your functions. Rather, all of your functions could return their numbers, then have a final function that is responsible for all of the printing. You could then customize your printing all in this final function, and that will be less cumbersome.

Can you elaborate on what you mean by more organized?