Nested loop results in table, Python

Question

I need to loop a computation over two lists of elements and save the results in a table. So, say that

months = [1,2,3,4,5]
Region = ['Region1', 'Region2']

and that my code is of the type

df=[]
for month in month:
    for region in Region:
        code 
        x = result
        df.append(x)

What I cannot achieve is rendering the final result in a table in which the rows are regions and coumns are months

                 1            2          3          4          5

    Region1      a            b          c          d          e
    
    Region2      f            g          h          i          j

What are the variables code and result in your code ? In for month in month: the second month should have an s at the end. — AlexisG
– AlexisG, Commented Sep 24, 2020 at 12:45
Sorry for missing the s. As for code, it is not a variable (I didn't want to write all the steps of my computation. So code is the what happens within the loop. result is the value obtained at the end of each loop. — Serge de Gosson de Varennes
– Serge de Gosson de Varennes, Commented Sep 24, 2020 at 12:54

AlexisG · Accepted Answer · 2020-09-24 13:28:04Z

2

Assuming that there is the right numbers of items in result

result = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']
months = [1, 2, 3, 4, 5]
Region = ['Region1', 'Region2']
df = pd.DataFrame([[Region[i]] + result[i*len(months): ((i+1)*len(months))] for i in range(len(Region))], columns=["Region"] + months).set_index("Region")

Output

         1  2  3  4  5
Region                
Region1  a  b  c  d  e
Region2  f  g  h  i  j

This part

[[Region[i]] + result[i*len(months): ((i+1)*len(months))] for i in range(len(Region))]

is equivalent to something like this

res = []
for i in range(len(Region)):
    row = [Region[i]] + result[i*len(months): ((i+1)*len(months))]
    res.append(row)

where I use the length of Region to slice result in equals part for each row. And I add the name of the region at the begging of the row.

edited Sep 24, 2020 at 13:28

answered Sep 24, 2020 at 12:43

AlexisG

2,4943 gold badges13 silver badges25 bronze badges

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

2 Comments

Serge de Gosson de Varennes Over a year ago

This is great, but I still can't make it populate the dataframe with the results result = ['a','b','c','d','e','f','g']

Serge de Gosson de Varennes Over a year ago

This is brilliant!! Thank you!!

gtomer · Accepted Answer · 2020-09-24 13:25:44Z

1

Another solution - more lines of code:

import pandas as pd
import ast
months = [1,2,3,4,5]
Regions = ['Region1', 'Region2']
       
df = pd.DataFrame()
for region in Regions:
    row = '{\'Region\': \'' +  region +'\', '
    for month in months:
        # put your calculation code
        x = month + 1
        row = row + '\'' + str(month) + '\':[' + str(x) + '],'
    row = row[:len(row)-1] + '}'
    row = ast.literal_eval(row)
    df = df.append(pd.DataFrame(row))
df

answered Sep 24, 2020 at 13:25

gtomer

6,6141 gold badge14 silver badges29 bronze badges

Comments

Renny Juhl · Accepted Answer · 2020-09-24 13:42:25Z

0

This might work, depending on what and how y want the results.

import pandas as pd
months = [1, 2, 3, 4, 5]
Region = ['Region1', 'Region2']

df = pd.DataFrame(columns=[1, 2, 3])  # just to put in something
value = 59
for r in Region:
    value += 5
    for m in months:
        df.loc[r, m] = chr(m+value)

answered Sep 24, 2020 at 13:42

Renny Juhl

12 bronze badges

Collectives™ on Stack Overflow

Nested loop results in table, Python

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related