Python: How to create new variable in each iteration of a for loop?

Question

I need to create a long text string out of 3 lists. This text string has to be in a very specific format where there's an element from each list separated by a space, and each group has a semicolon afterwards. The below script should run:

import math

reclassInt = [1, 2, 3, 4, 5, 6]
minValueRange = [512, 550.0, 600.0, 650.0, 700.0, 750.0]
maxValueRange = [550.0, 600.0, 650.0, 700.0, 750.0, 755]

for numbers in reclassInt:
    newNums = numbers-1
    longString = str(minValueRange[newNums]) + " " + str(maxValueRange[newNums]) + " " + str(reclassInt[newNums]) + ";" 
    print longString

This will return 6 lines, the first being:

512 550.0 1;

Instead of printing these strings, I want to set a variable to each of them. I want this variable to have a unique name for each iteration of the loop( based on reclassInt items).

Ideally this could create variables like line1, line2, ect to equal the string outputs from each iteration. Then I could string these together outside the loop to get my desired string.

To be clear my end goal is this exact string:

"512 550.0 1;550.0 600.0 2;600.0 650.0 3;650.0 700.0 4;700.0 750.0 5;750.0 755 6;"

Thanks All,...

dynamic naming is almost always a bad idea. Usually it's much better to use a dict. (also, your code could be cleaned up a bit by using zip :-) — mgilson
– mgilson, Commented Dec 9, 2013 at 7:46
Looks like a list might be better here. I don't think the items really need to be named based on reclassInt; it looks like all that's really needed is that they be in order and accessible by index. — user2357112
– user2357112, Commented Dec 9, 2013 at 8:11

Burhan Khalid · Accepted Answer · 2013-12-09 10:16:54Z

2

How about this:

>>> d = {i+1:v for i,v in enumerate(zip(minValueRange, maxValueRange))}
>>> d
{1: (512, 550.0),
 2: (550.0, 600.0),
 3: (600.0, 650.0),
 4: (650.0, 700.0),
 5: (700.0, 750.0),
 6: (750.0, 755)}

Then to print your string:

>>> for k,v in d.iteritems():
...    print('{} {} {};'.format(v[0], v[1], k))
...
512 550.0 1;
550.0 600.0 2;
600.0 650.0 3;
650.0 700.0 4;
700.0 750.0 5;
750.0 755 6;

To get the string in one line, as per your update:

>>> ''.join('{} {} {};'.format(v[0], v[1], k) for k,v in d.iteritems())
'512 550.0 1;550.0 600.0 2;600.0 650.0 3;650.0 700.0 4;700.0 750.0 5;750.0 755 6;'

Also if that's your only requirement you don't need to generate the dictionary and can combine everything into this:

>>> ''.join('{} {} {};'.format(v[0], v[1], k+1) for k,v in enumerate(zip(minValueRange, maxValueRange)))
'512 550.0 1;550.0 600.0 2;600.0 650.0 3;650.0 700.0 4;700.0 750.0 5;750.0 755 6;'

edited Dec 9, 2013 at 10:16

answered Dec 9, 2013 at 7:55

Burhan Khalid

175k20 gold badges254 silver badges291 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

therMapper Over a year ago

I added to the original question showing the exact syntax I need. I did not get this to work. Thanks...

therMapper Over a year ago

Thanks- your 1 line does it all.

aIKid · Accepted Answer · 2013-12-09 07:52:35Z

2

To make things much simpler, and better, you can use a dictionary:

longStrings= {}
for numbers in reclassInt:
    newNums = numbers-1
    d["longString_%d"%numbers] = str(minValueRange[newNums]) + " " + str(maxValueRange[newNums]) + " " + str(reclassInt[newNums]) + ";" 
    bs = "ls" + str(numbers)

answered Dec 9, 2013 at 7:52

aIKid

28.5k5 gold badges41 silver badges65 bronze badges

1 Comment

therMapper Over a year ago

I tried this but when I added the command to print longStrings and it was still empty- {}

Collectives™ on Stack Overflow

Python: How to create new variable in each iteration of a for loop?

2 Answers 2

2 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related