Pandas中将字符串（object）格式的列，强制转换为浮点型的列

import pandas as pd
df = pd.DataFrame([['11.0' ,1,2,3],
                   ['22.0' ,4,5,6],
                   ['33.0' ,7,8,9]], columns = ['a','b','c','d'])

df['a'] = pd.to_numeric(df['a'],errors = 'coerce')

列 a 的类型，是 object 类型。 pd.to_numeric() 将这个对象转换为 float

errors=coerce 将不能转换的字符替换为空值: NaN