Title: Search A Pandas Column For A Value
Slug: pandas_search_column_for_value
Summary: Search A Pandas Column For A Value
Date: 2016-05-01 12:00
Category: Python
Tags: Data Wrangling
Authors: Chris Albon



In [1]:

    
# Import modules
import pandas as pd



In [2]:

    
raw_data = {'first_name': ['Jason', 'Jason', 'Tina', 'Jake', 'Amy'], 
        'last_name': ['Miller', 'Miller', 'Ali', 'Milner', 'Cooze'], 
        'age': [42, 42, 36, 24, 73], 
        'preTestScore': [4, 4, 31, 2, 3],
        'postTestScore': [25, 25, 57, 62, 70]}
df = pd.DataFrame(raw_data, columns = ['first_name', 'last_name', 'age', 'preTestScore', 'postTestScore'])
df









    Out[2]:






  
    
      
      first_name
      last_name
      age
      preTestScore
      postTestScore
    
  
  
    
      0
      Jason
      Miller
      42
      4
      25
    
    
      1
      Jason
      Miller
      42
      4
      25
    
    
      2
      Tina
      Ali
      36
      31
      57
    
    
      3
      Jake
      Milner
      24
      2
      62
    
    
      4
      Amy
      Cooze
      73
      3
      70

Find where a value exists in a column



In [3]:

    
# View preTestscore where postTestscore is greater than 50
df['preTestScore'].where(df['postTestScore'] > 50)









    Out[3]:





0     NaN
1     NaN
2    31.0
3     2.0
4     3.0
Name: preTestScore, dtype: float64

	first_name	last_name	age	preTestScore	postTestScore
0	Jason	Miller	42	4	25
1	Jason	Miller	42	4	25
2	Tina	Ali	36	31	57
3	Jake	Milner	24	2	62
4	Amy	Cooze	73	3	70