Question

我有一些数据的数据帧df。而且我还有一个条件为selection的切片cond_1。

    def cond1(row):
        if some_condition_1:
            return True
        return False

    def cond2(row):
        if some_condition_2:
            return True
        return False

    selection = df[df.apply(cond1, axis=1)]

    # Some logic here
    #...
    #
    # Later:

但是我需要使用其他条件cond2附加一些数据那么我可以只使用selection扩展cond2还是让我selection2然后加入他们？

Answer 1

...
...

selection1 = dataframe based on some condition
selection2 = dataframe based on some condition

selection1 = selection1[selection1.apply(cond1, axis=1)]
selection2 = selection2[selection2.apply(cond2, axis=1)]

pd.concat([selection1, selection2])

Answer 2

您可以这样做

ind_cond1 = df.apply(cond1, axis=1)
ind_cond2 = df.apply(cond2, axis=1)

## if you want to slice df which matches either of the condition
or_cond = ind_cond1 | ind_cond2
df[or_cond]

## if you want to slice df which matches both condition
and_cond = ind_cond1 & ind_cond2
df[and_cond]

## you can also use other logical operation like xor, not etc

如何在熊猫中添加行以切片？

2 个答案: