CODEWITHSUNDEEP
stringpandaslistmax
corianne1234
corianne1234

Reputation: 724

pandas: get the maximum value of a list with string numbers

I have a dataframe df=pd.DataFrame({'xx':[['100','5','3'], ['5','40'], ['100']]}) and I would like to have the maximum of each list as a number. So I would like to get this:

xx
0   100
1   40
2   100

Is there a way to do this?

Upvotes: 1

Views: 2773

Answers (4)

Ubaid Khan
Ubaid Khan

Reputation: 1

import pandas

data = pandas.read_csv("weather_data.csv")
data_list = data["temp"].max()
print(data_list)

in the file of weather_data.csv we have a list which we called temp if we need temp list maixmum value we can apply this method

Upvotes: 0

kederrac
kederrac

Reputation: 17322

you can use pandas.Series.apply:

df['max_xx'] = df['xx'].apply(lambda x: max(map(int, x)))
df['max_xx']

output:

0    100
1     40
2    100

if you want to use pandas.DataFrame.assign you can use:

df.assign(max_xx=lambda x: [max(map(int, l)) for l  in x.xx])

Upvotes: 0

anky
anky

Reputation: 75080

Adding another pandas method using series.explode to explode the series of lists into 1 series , then using series.astype convert to int , then take max grouped by index:

df['max_col'] = df['xx'].explode().astype(int).max(level=0)

#or:-> df['xx'].explode().astype(int).groupby(level=0).max()

0    100
1     40
2    100

Upvotes: 1

jezrael
jezrael

Reputation: 862831

Convert values to integers and get max value:

df['xx'] = df['xx'].map(lambda x: max(int(y) for y in x))

Or use list comprehension:

df['xx'] = [max(int(y) for y in x) for x in df['xx']]

print(df)
    xx
0  100
1   40
2  100

Upvotes: 1

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