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I have a problem with 'loc' and'iloc' .So I have a list and a data frame, I want to check if the data in list and date in data frame of a column is matching. if matching I need to copy it to a new data frame. I am half way but I don't know how to copy the rows from a data frame to new one based on the index. How do we do that?

Code:

d = {'col1': [1, 2,3,5,6], 'col2': [3, 4,5,6,7]}
cols = list(df.columns)
df1=pd.DataFrame(columns=cols) 
lst=['1','2']
df1 = pd.DataFrame()
for index,v in df['col1'].iteritems():
    for l in lst:
        if l == v:
            df1 = df.loc[index]

which gives nothing(empty data frame):

col1    col2

Actual output:

df1 =
   col1 col2
0   1   3
1   2   4
Improve this question
5
  • 1
    You have data type problems. lst is a string, your default index in df is an integer. l will not equal v. change to lst=[1,2] Commented Mar 18, 2021 at 18:46
  • 1
    loc is using label based index, iloc is using integer position based indexing. Confusion happens mostly because with the default range index of a dataframe, the indexing are integer matching exactly the position based of the index, thus either will work. Commented Mar 18, 2021 at 18:49
  • 2
    aside from the data type problem, try isin and boolean indexing df.loc[df['col1'].isin(lst)]. Commented Mar 18, 2021 at 18:52
  • @ScottBoston Thanks for the explanation .Yes, it did Commented Mar 18, 2021 at 19:07
  • @QuangHoang Your approach was simple.Thanks alot :) helped me alot Commented Mar 18, 2021 at 19:08
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