Pandas 数据框循环

Question

I'm stuck with the code below. Basically, I am looping through the first column of 2 dataframes with the loop variables 'analyticalname' and 'fedbatchname'. If these two variables find a match in each dataframe, then I want to access that element of the dataframe based on the value of the loop variable. When I run the code, however, I get a key error that originates at the line after the if statement. In essence, I am asking how to access an element of a dataframe based on a loop variable. Any suggestions?

import pandas as pd
analyticaldata = pd.read_csv('SE-HPLC.csv', usecols = ['Sample ID','% 
Aggregate','% Monomer','% Fragment']) #loading data into pandas DataFrame
fedbatchdata = pd.read_csv('Culture Day Sheet.csv',usecols = 
['RUN_NUMBER','% Aggregate','% Monomer','% Fragment'])

for analyticalname in analyticaldata['Sample ID']: #for each element in 
first column of SE-HPLC worksheet
for fedbatchname in fedbatchdata['RUN_NUMBER']: #for each element in first column of Culture Day worksheet
    if analyticalname == fedbatchname: #if any of the names match
        fedbatchdata.ix[fedbatchdata.fedbatchname,'% Aggregate'] = analyticaldata[analyticalname]['% Aggregate']
        fedbatchdata.ix[fedbatchdata.fedbatchname,'% Monomer'] = analyticaldata.ix[analyticalname,'% Monomer']                  
        fedbatchdata.ix[fedbatchdata.fedbatchname,'% Fragment'] = analyticaldata.ix[analyticalname,'% Fragment']

EDIT: Here is some sample data for both dataframes, I apologize for leaving that out. The fedbatch dataframe is meant to be empty, I am trying to copy the values from the analytical dataframe into the fedbatch dataframe.

Analytical dataframe:
SAMPLE_ID:    % Aggregate    % Monomer    % Fragment
A               2             4             1.5
B               1             4             6
C               5             5             2.1
D               3             7.1           10

Fed Batch Dataframe:
RUN_NUMBER:    % Aggregate    % Monomer    % Fragment
B                                        
A                                                                                   
C
D                                                  

Answer 1

Use merge with rename column for avoid it in output DataFrame with select only column RUN_NUMBER from fedbatchdata :

df = (fedbatchdata[['RUN_NUMBER']]
                    .merge(analyticaldata.rename(columns={'Sample ID':'RUN_NUMBER'}), 
                          on=['RUN_NUMBER'], 
                          how='left'))
print (df)
  RUN_NUMBER  % Aggregate  % Monomer  % Fragment
0          B            1        4.0         6.0
1          A            2        4.0         1.5
2          C            5        5.0         2.1
3          D            3        7.1        10.0