"not all arguments converted during string formatting" when setting multiple global variables

Question

I wanted to generate unique variable using iteration. I tried writing a code using globals() function but for some reason its not working.

for i in (range(0,7)): 
    for v in range(0,7): 
        globals()['element%s' % (i,v)] = []

You can use a [dictionary](https://docs.python.org/3/tutorial/datastructures.html#dictionaries) directly — BlackBear, Jun 22 '20 at 19:43
"for some reason its not working" -> Could you be more specific? Do you get an error message or some other indicator of what went wrong? — Niklas Mertsch, Jun 22 '20 at 19:45
Yes. This is the error. 'TypeError Traceback (most recent call last) in 1 for i in (range(0,7)): 2 for v in range(0,7): ----> 3 globals()['element%s' % (i,v)] = [] 4 TypeError: not all arguments converted during string formatting' — Vivek, Jun 22 '20 at 19:48

score 0 · Answer 1 · answered Jun 22 '20 at 19:48

0

The problem comes with the text formating.

Try globals()[f'elements{i,v}'] = [] instead.

answered Jun 22 '20 at 19:48

borjasanlei

49
3

It does create the variables but when I call that variable its shows this error: 'name 'elements' is not defined'. I'm looking for output something like element00, element01, element02 and so on. – Vivek Jun 22 '20 at 20:06

score 0 · Answer 2 · answered Jun 22 '20 at 19:50

0

You can use something like this. Note that modifying globals() is rarely a good idea, have a look at this instead.

for i in range(5):
  globals()['myvar'+str(i)] = i**2

print(myvar2)
print(myvar3)

Output:

4
9

answered Jun 22 '20 at 19:50

PApostol

2,152
2
11
21

score 0 · Accepted Answer · answered Jun 22 '20 at 20:06

You honestly just shouldn't play with globals (reading material). But your error comes from the fact that the arguments you're trying to turn to a string (i, v) have size 2, and there's a single place where you demanded a conversion: the %s. If you want it to work there needs to be 2X %s in your string:

for i in (range(0,4)):
    for v in range(0,3):
        print('%selement%s' % (i,v))

0element0
0element1
0element2
1element0
1element1
1element2
2element0
2element1
2element2
3element0
3element1
3element2

"not all arguments converted during string formatting" when setting multiple global variables

3 Answers3