using pass in if statement in lambda function python

Question

I have a df in pandas, python with mostly float values but contains a few strings and looks as such:

index  cashflow    date          changeinvalue
0      5000        2019-12-31    9300  
1      4000        2019-12-31    -4000  
2      -2000       2019-12-31    -9000

I am trying to use an apply function and lambda function to turn all values in the dataframe to absolute values. However I think I may be using the lambda function incorrectly as using the following code I get the following error:

df.apply(lambda x: abs(x) if isinstance(x, str) == False else pass)

SyntaxError: invalid syntax

Would anyone be able to help me? Thanks

jezrael · Accepted Answer · 2021-02-05 12:14:59Z

1

Select only numeric columns by DataFrame.select_dtypes and convert them to absolute values:

cols = df.select_dtypes(np.number).columns
df[cols] = df[cols].abs()
print (df)
       cashflow        date  changeinvalue
index                                     
0          5000  2019-12-31           9300
1          4000  2019-12-31           4000
2          2000  2019-12-31           9000

Your solution failed, because need test elementwise, not by columns in apply.

So if need test each value separately use DataFrame.applymap, then test numeric int and float for absolute values and all another values not change (so return back):

df = df.applymap(lambda x: abs(x) if isinstance(x, (int, float)) else x)

edited Feb 5, 2021 at 12:14

answered Feb 5, 2021 at 12:11

jezrael

868k103 gold badges1.4k silver badges1.3k bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Vishnudev Krishnadas Over a year ago

It might be worth mentioning why the OP's code errored. The pass issue.

Hamish Gibson · Accepted Answer · 2021-02-05 12:11:12Z

0

You can do

df.columns = df.columns.abs()

That should work.

answered Feb 5, 2021 at 12:11

Hamish Gibson

2565 silver badges19 bronze badges

Comments

Epimetheus · Accepted Answer · 2021-02-05 12:11:44Z

0

apllying per column should do the job.

i.e.

df.columns = df.columns.abs()

answered Feb 5, 2021 at 12:11

Epimetheus

3933 silver badges20 bronze badges

Collectives™ on Stack Overflow

using pass in if statement in lambda function python

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related