Appending csv values to list based on condition using pandas

Question

I was trying to open a csv file panda_try.csv. What i want to do is to compare the elements in the first two columns from the file and check if they are equal. If they are equal, I want to append it in a list called selfloop_appender and then calculate the length of list. But when i try to `print (selfloop_appender)', i donot get any output and error. Any help will be great.

import pandas as pd
df = pd.read_csv('/home/venkat/Desktop/panda_try.csv')
xy_data = df.iloc[:,0:2]

def self_loops(xy_data):
    selfloop_appender = []
    for i,j in xy_data:
        if i == j:
            selfloop_appender.append([i,j])
            print("the number of self_loops are:") + len(str(selfloop_appender))

    return selfloop_appender
self_loops(xy_data)

BENY · Accepted Answer · 2018-04-15 16:58:41Z

2

You can try nunique, if it equal to 1 , mean i=j.

xy_data[xy_data.nunique(1)==1].iloc[:,1].tolist()

Update

df=pd.DataFrame({'A':[1,2,3],'B':[1,2,6]})
df.nunique(1)
Out[440]: 
0    1
1    1
2    2
dtype: int64

If return 1 means A=B

Then we using eq(equal to ==) to slice the row we need

df[df.nunique(1).eq(1)]
Out[442]: 
   A  B
0  1  1
1  2  2
df[df.nunique(1).eq(1)].iloc[:,1]
Out[443]: 
0    1
1    2
Name: B, dtype: int64
df[df.nunique(1).eq(1)].iloc[:,1].tolist()
Out[444]: [1, 2]

edited Apr 15, 2018 at 16:58

answered Apr 15, 2018 at 16:49

BENY

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1 Comment

Venkat kamal Over a year ago

I am not able to understand, can u make the edit in the code?

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