comparing values from different dataframes line by line, python

问题

I have two dataframes with different numbers of lines.

X&Y are coordinates in 2D position

DF1:

X,Y,C
1,1,12
2,2,22
3,3,33
4,4,45
5,5,43
6,6,56

DF2: X,Ystart squere next two X,Y END squere

X,Y,X1,Y1
1,1,3,3
2,2,4,4

part of my code:

A = (abs(DF1['X']).values > abs(DF2['X']).values)
B = (abs(DF1['Y']).values > abs(DF2['Y']).values)
C = (abs(DF1['X']).values < abs(DF2['X1']).values)
D = (abs(DF1['Y']).values < abs(DF2['Y1']).values)
RESULT = A & B & C & D
result=DF1[RESULT]

ALSO: i can use only 2 columns from DF2, and in RESULT will be used only A & B, its only example. Right now 2times X and Y showing me the range of values.

When DF2 have only one line, there is OK. But with more than one i have received: ValueError: operands could not be broadcast together with shapes I know that i need to create a rule that all lines will be compared, but i don't know how, i have tried with diff, but no good results.

OUTPUT: I need to delete this error and start using line by line. For each line in DF2 i need separate result: for line 1:

X,Y,C
2,2,22

For line 2

X,Y,C
3,3,33

And after each checking the line i need to save dataframes results to one file So in this example in one file there will be``

2,2,22
3,3,33

Thanks for advice

EDIT: for Tbaki

def isInSquare(row, df2):
    df2=result_from_other_def1.df1
    df1=result_from_other_def2.df2

    if (row.X > df2.iloc[0].X) and (row.Y > df2.iloc[1].Y):
        if (row.X < df2.iloc[0].X1) and (row.Y < df2.iloc[1].Y2):
            if (row.X < df2.iloc[1].X) and (row.Y < df2.iloc[1].Y):
                if (row.X > df2.iloc[0].X) and (row.Y > df2.iloc[1].Y2):
                    return True
    return False

DF1.apply(lambda x: isInSquare(x,DF2),axis= 1)# if i will leave this line here, tk inter will run it automaticly so i my opiniot this should be inside definition. Also i dont know how many lines will be in DF1 and in DF2. Thanks

回答1:

Check this code, checking for a 5x5 square.

DF1 = pd.DataFrame({"X":[1,2,3,4,5,6],"Y":[1,2,3,4,5,6],"C":[12,22,33,45,13,56]})
DF2 = pd.DataFrame({"X":[1,5],"Y":[1,1],"X1":[5,1],"Y1":[5,5]})

def isInSquare(row, df2):
    c1 =  (row.X > df2.iloc[0].X) and (row.Y > df2.iloc[0].Y)
    c1 = c1 and  (row.X < df2.iloc[0].X1) and (row.Y < df2.iloc[0].Y1)
    c1 = c1 and (row.X < df2.iloc[1].X) and (row.Y > df2.iloc[1].Y)               
    c1 = c1 and (row.X > df2.iloc[1].X1) and (row.Y < df2.iloc[1].Y1)
    return c1    

DF_NEW = DF1[DF1.apply(lambda x: isInSquare(x,DF2),axis= 1)]

output

    C   X   Y
1   22  2   2
2   33  3   3
3   45  4   4

if you want to keep the max C:

DF_NEW = DF_NEW.groupby(["X","Y"]).max().reset_index()

来源：https://stackoverflow.com/questions/44456526/comparing-values-from-different-dataframes-line-by-line-python

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python

dataframe

compare

valueerror