循环打印列表格式化

Question

I wanted to create a list of factors from any given number only using the formula below. I am not allowed to use list therefore, I have imitate using strings as follows:

for example and lets say we choose num=12:

def factors(num):
    i=1 
    while i <= num :
        if num % i == 0:
            print i

        i = i + 1

this code prints:

1
2
3
4
6
12

Without using lists, for loops, int, function and can only use strings,

how do i format the loop outputs to make it look like this?:

[1, 2, 3, 4 ,6 ,12]

I tried doing this first:

num = 12
i = 1
while i <= num :
    if num % i == 0:
        a=str("[")+str(i)+", "+str("]")
        print a

    i = i + 1

This prints:

[1, ]
[2, ]
[3, ]
[4, ]
[6, ]
[12, ]

Can anyone help or suggest where I can put that print state or how do i modify it? Thanks!

Answer 1

def factors(num):
    i=1
    result="["
    while i <= num :
        if num % i == 0:
            result=result+str(i)+","
        i+=i

    result=result[:-1]+"]"
    print result

factors(12)

Output > [1,2,4]

Answer 2

you can use use a print statement that ends with a comma to not insert a new line when a second print statement is used then you just need to make sure the first time in prints "[" and the last time it prints "]"

for example

print "hello ",
print "world"

would return >>>hello world

the code would look something like this

def factors(num):
    i=1 
    while i <= num :
        if i == 1:
            if num % i == 0:
                print "[",
            else:
                 print "[",
        if i == num:
            print "%s]"%(i)
        elif num % i == 0:
            if i == num:
               print i,"]"
            else:
                print "%s,"%(i),




        i = i + 1

Answer 3

You can concatenate each str(i) to string a by += ,

def factors(num):
    i = 1
    a = "["
    while i < num :
        if num % i == 0:
            a+=str(i)+", "
        i = i + 1
    print(a + str(num) + str("]"))

factors(12)

Output:

   [1, 2, 3, 4, 6, 12]

Answer 4

def factors(num):
    i = 1
    factors = []
    while i <= num:
        if num % i == 0:
            factors.append(i)

    i += 1

    print factors

factors(12)

This adds all the factors to a table called factors, and then when all the factors are added, the table factors is printed out.