How do I convert an object to a float in Pandas?

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You can use one of the following methods to convert a column in a pandas DataFrame from object to float:

Method 1: Use astype()

df['column_name'] = df['column_name'].astype(float)

Method 2: Use to_numeric()

df['column_name'] = pd.to_numeric(df['column_name'])

Both methods produce the same result.

The following examples show how to use each method with the following pandas DataFrame:

import pandas as pd

#create DataFrame
df = pd.DataFrame({'team': ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H'],
                   'points': ['18', '22.2', '19.1', '14', '14', '11.5', '20', '28'],
                   'assists': [5, 7, 7, 9, 12, 9, 9, 4]})

#view DataFrame
print(df)

  team points  assists
0    A     18        5
1    B   22.2        7
2    C   19.1        7
3    D     14        9
4    E     14       12
5    F   11.5        9
6    G     20        9
7    H     28        4

#check data type of each column
print(df.dtypes)

team       object
points     object
assists     int64
dtype: object

Method 1: Use astype() to Convert Object to Float

The following code shows how to use the astype() function to convert the points column in the DataFrame from an object to a float:

#convert points column from object to float
df['points'] = df['points'].astype(float)

#view updated DataFrame
print(df)

  team  points  assists
0    A    18.0        5
1    B    22.2        7
2    C    19.1        7
3    D    14.0        9
4    E    14.0       12
5    F    11.5        9
6    G    20.0        9
7    H    28.0        4

#view updated data types
print(df.dtypes)

team        object
points     float64
assists      int64
dtype: object

Notice that the points column now has a data type of float64.

Method 2: Use to_numeric() to Convert Object to Float

The following code shows how to use the to_numeric() function to convert the points column in the DataFrame from an object to a float:

#convert points column from object to float
df['points'] = pd.to_numeric(df['points'], errors='coerce')

#view updated DataFrame
print(df)

  team  points  assists
0    A    18.0        5
1    B    22.2        7
2    C    19.1        7
3    D    14.0        9
4    E    14.0       12
5    F    11.5        9
6    G    20.0        9
7    H    28.0        4

#view updated data types
print(df.dtypes)

team        object
points     float64
assists      int64
dtype: object

Notice that the points column now has a data type of float64.

Also note that this method produces the exact same result as the previous method.