Having the two vectors below, I am trying to get the desired output without a for loop.
re = [1,2]
po = [1, 3, 5, 10, 20]
Desired output:
re po
1 1
1 3
1 5
1 10
1 20
2 1
2 3
2 5
2 10
2 20
Any assistance is appreciated.
CodePudding user response：
You can multiply each list by the length of the other and pass it to pd.DataFrame:
out = pd.DataFrame([re*len(po), po*len(re)], index=['re','po']).T.sort_values(by=['re','po'])
Output:
re po
0 1 1
6 1 3
2 1 5
8 1 10
4 1 20
5 2 1
1 2 3
7 2 5
3 2 10
9 2 20
CodePudding user response：
You can use the merge function to do a cross merge. To do this, you would make each vector a dataframe then merge them like this :
re = [1,2]
po = [1, 3, 5, 10, 20]
reDf = pd.DataFrame({"re":re})
po = pd.DataFrame({"po":po})
repo = re.merge(po,how="cross")
Or if you don't want to define new variables:
re = [1,2]
po = [1, 3, 5, 10, 20]
repo = pd.DataFrame({"re":re}).merge(pd.DataFrame({"po":po}), how="cross")
Output:
re po
1 1
1 3
1 5
1 10
1 20
2 1
2 3
2 5
2 10
2 20
CodePudding user response：
You can use list comprehension: output = [[x,y] for x in re for y in po]
Here's the full code.
import pandas as pd
re = [1,2]
po = [1, 3, 5, 10, 20]
output = [[x,y] for x in re for y in po]
df = pd.DataFrame(output)
df.columns = ['re', 'po']
display(df)
Output:
re po
0 1 1
1 1 3
2 1 5
3 1 10
4 1 20
5 2 1
6 2 3
7 2 5
8 2 10
9 2 20
CodePudding user response：
You can use itertools.product and the DataFrame constructor:
re = [1,2]
po = [1, 3, 5, 10, 20]
from itertools import product
df = pd.DataFrame(product(re, po), names=['re', 'po'])
You can also use pandas.MultiIndex.from_product and transform to_frame:
re = [1,2]
po = [1, 3, 5, 10, 20]
df = pd.MultiIndex.from_product([re, po], names=['re', 'po']).to_frame(index=False)
Output:
re po
0 1 1
1 1 3
2 1 5
3 1 10
4 1 20
5 2 1
6 2 3
7 2 5
8 2 10
9 2 20