在数据框中查找特定值并记录（行、列）索引对

Question

I have a Pandas data frame that looks like the following:

Now, I want to go through the entire data frame and record the column and row index pairs (shown as just numbers for this example) for any value that is less than 0.12. For example, I want to identify 0.105263, record that value, and record that it is located in row 4, column 2. Are there any efficient methods for traversing a data frame and storing this kind of data in a new data frame?

My goal is to have the output look like the following:

Row  Col  Value
==================
4     2   0.105263
... 

Answer 1

You can try

out = (df[df.le(0.12)]
       .stack().reset_index()
       .rename(columns={'level_0':'row', 'level_1':'col', 0: 'val'}))