PANDAS left
时间: 2023-09-27 10:07:48 浏览: 48
Pandas中的left merge是指将两个数据框按照left数据框的键进行合并,保留left数据框中的所有行,而右数据框中没有匹配的行则填充为NaN。使用Pandas的merge方法,可以通过指定参数how='left'和on='键名'来进行left merge操作。例如,df_1.merge(df_2, how='left', on='userid')会将df_1和df_2按照userid键进行合并,保留df_1中的所有行,右数据框df_2中没有匹配的行则用NaN填充。左连接与右连接在操作上是相似的,只需要交换两个数据框的位置即可,返回的结果是一样的。<span class="em">1</span><span class="em">2</span><span class="em">3</span>
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