How to add value if condition match, python

Question

I want to add "1" in each row for columns "Score" where the below statement is true,

import pandas as pd
import numpy as np


df = pd.read_csv(Path1 + 'Test.csv')
df.replace(np.nan, 0, inplace=True)
df[(df.Day7 >= 500)]

Sample Value

Output

Please add samples in text form of input and expected output in your post and do let us know then. — RavinderSingh13, Mar 17 '19 at 12:09
@RavinderSingh13 added sample value and require output details — MD SAQUIB NASIR KHAN, Mar 17 '19 at 12:14
As mentioned above it is always recommended to add samples of input and expected output in TEXT form, kindly do edit your post and let us know then. — RavinderSingh13, Mar 17 '19 at 12:36

score 1 · Answer 1 · edited Mar 17 '19 at 12:32

1

You are halfway there. Just use df.loc[mask, "Score"] = 1:

import numpy as np
import pandas as pd

df = pd.DataFrame({"Day7":np.random.rand(5)*1000,
                   "Score": np.random.rand(5)})
print(df)
df.loc[(df.Day7>=500), "Score"] = 1
print(df)

edited Mar 17 '19 at 12:32

jezrael

822,522
95
1,334
1,252

answered Mar 17 '19 at 12:11

f.wue

837
8
15

RavinderSingh13 · Accepted Answer · 2019-03-18T06:28:19.830

1

Could you please try following.

df['score']=np.where(df['Day7']>=500,1,"")

Or as per OP's comment(adding @anky_91's enhanced solution here):

np.where((df['Day7']>=500)&(df['Day7']<1000),1,"")

When we print the value of df following will be the output.

    Cat          Day7    score
0   Advertisir   145    
1   Blogs        56 
2   Business     92 
3   Classfied    23 
4   Continuin    110    
5   Corporate    1974     1

edited Mar 18 '19 at 06:28

answered Mar 17 '19 at 12:30

RavinderSingh13

130,504
14
57
93

1

yep, this is a good usecase for np.where also. +1 – anky Mar 17 '19 at 13:02
1

@anky_91, Thanks for encouragement buddy, learning from all greats(you are one of them too) pandas, cheers – RavinderSingh13 Mar 17 '19 at 13:56
1

Ha ha i am no where close. :D we all are learning. :) Thank you – anky Mar 17 '19 at 13:57
@anky_91 any suggestion if wanted to use Day7 >= 500 with < 1000, and want same type of output – MD SAQUIB NASIR KHAN Mar 18 '19 at 06:03
1

@MDSAQUIBNASIRKHAN use `np.where((df['Day7']>=500)&(df['Day7']<1000),1,"")` – anky Mar 18 '19 at 06:06
@anky_91 hi, is it possible to put a condition like Day7 >= 500 scores 1, if >=100 & < 500 sore 2, else 3. – MD SAQUIB NASIR KHAN Mar 18 '19 at 14:16
1

@MDSAQUIBNASIRKHAN same like you do in np.where, but this time use [np.select](https://docs.scipy.org/doc/numpy/reference/generated/numpy.select.html) for multiple conditions: – anky Mar 18 '19 at 14:18

score 0 · Answer 3 · answered Mar 17 '19 at 12:10

0

df = df.assign(Score=0)
df.Score = df.Day7 >= 500

answered Mar 17 '19 at 12:10

jgoday

2,768
1
18
17

How to add value if condition match, python

3 Answers3