Retrieving series rows given a condition

Question

Consider the following series which represents the distance between location a and locations b, c, d:

Now, what I'm trying to do is retrieve all location names that are within a certain distance from a.

For example, I would like to print out all variables that are within a 15 unit distance from a, excluding a, which would be b and c.

b

c

I've tried creating an empty list and then using a for loop to append to that list but to no avail, so I'm obviously missing something.

Does this answer your question? [How to select rows from a DataFrame based on column values?](https://stackoverflow.com/questions/17071871/how-to-select-rows-from-a-dataframe-based-on-column-values) — Shubham Sharma, Jun 01 '20 at 13:04
@timgeb thanks for pointing that out, I have edited the post. There are no negative values so it does not matter. — grimrol123, Jun 01 '20 at 13:05
@ShubhamSharma it's helpful but does not really answer my question no. I had already managed to retrieve the rows but I'm trying to print the row names that satisfy the condition. — grimrol123, Jun 01 '20 at 13:12
@grimrol123 Can you include a snippet of code showing what you have tried? — Shubham Sharma, Jun 01 '20 at 13:20

score 1 · Answer 1 · answered Jun 01 '20 at 13:18

Forget loops, pandas and numpy already have builtin functions that make the job. In this case you can use np.where.

import pandas as pd
import numpy as np
df = pd.Series({'a':0, 'b':10, 'c':12, 'd':21}, index=['a', 'b', 'c', 'd'])
df.iloc[np.where((df<=15) & (df.index !='a'))]

score 0 · Answer 2 · answered Jun 01 '20 at 13:18

0

You can do this, i assumed the first column is an index:

print(df[(df['a'] < 15) & (df.index != 'a')])

      a
loc
b    10
c    12

answered Jun 01 '20 at 13:18

NYC Coder

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score 0 · Accepted Answer · answered Jun 01 '20 at 13:21

0

Try this:

dist = 15
val = list(df.loc[(df['a'] < dist) & (df.index != 'a')].index)
print(val)

Output:

['b', 'c']

answered Jun 01 '20 at 13:21

Anshul

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Retrieving series rows given a condition

3 Answers3