如何使用 pandas 和 python 从列中减去单个值
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How can i substract a single value from a column using pandas and python
提问by jax
i have one data frame suppose:
我有一个数据框假设：
name age hb
ali 34 14
jex 16 13
aja 24 16
joy 23 12
i have a value say "5" that i want to substract from each member of column "hb"
我有一个值说“5”，我想从“hb”列的每个成员中减去
new column could be:
新列可能是：
hb
9
8
11
7
What is the best method to do this...
什么是最好的方法来做到这一点...
thanks and regards.
感谢致敬。
采纳答案by Anand S Kumar
Simply subtract the scalar value from the pandas.Series, for numerical columns pandas would automatically broadcast the scalar value and subtract it from each element in the column. Example -
只需从 中减去标量值pandas.Series，对于数字列，pandas 会自动广播标量值并从列中的每个元素中减去它。例子 -
df['hb'] - 5 #Where `df` is your dataframe.
Demo -
演示 -
In [43]: df
Out[43]:
name age hb
0 ali 34 14
1 jex 16 13
2 aja 24 16
3 joy 23 12
In [44]: df['hb'] - 5
Out[44]:
0 9
1 8
2 11
3 7
Name: hb, dtype: int64
回答by Hackaholic
try this:
尝试这个：
df["hb"] - 5
df["hb"]will select hbcolumn and subtract 5 from it
df["hb"]将选择hb列并从中减去 5
回答by Colin Anthony
You can also do this using the pandas.apply function
您也可以使用 pandas.apply 函数执行此操作
df["hb"] = df["hb"].apply(lambda x: x - 5)
df["hb"] = df["hb"].apply(lambda x: x - 5)
回答by Durmus
If you are using this:
如果你正在使用这个：
df['hb'] - 5
you will get a new single column. But if you want to keep the rest then you have to use:
你会得到一个新的单列。但是，如果您想保留其余部分，则必须使用：
df['hb'] -= 5
