Transform a Pandas Dataframe Column and Index to Values

Question

I have a dataframe in a "yes/no" format like

    7   22
1   NaN t
25  t   NaN

where "t" stands for yes and I need to transform it to a X-Y table since the column name is the X coordinate and the index is the Y coordinate:

  X  Y
1 22  1
2  7 25

a pseudo-code like:

if a cell = "t":
     newdf.X = df.column(t)
     newdf.Y = df.index(t)

Answer 1

Try this:

# Use np.where to get the integer location of the 't's in the dataframe
r, c = np.where(df == 't')

# Use dataframe constructor with dataframe indexes to define X, Y
df_out = pd.DataFrame({'X':df.columns[c], 'Y':df.index[r]})
df_out

Output:

    X   Y
0  22   1
1   7  25

Update to address @RajeshC comment:

Given df,

      7   22
1   NaN    t
13  NaN  NaN
25    t  NaN

Then:

r, c = np.where(df == 't')
df_out = pd.DataFrame({'X':df.columns[c], 'Y':df.index[r]}, index=r)
df_out = df_out.reindex(range(df.shape[0]))
df_out

Output:

     X     Y
0   22   1.0
1  NaN   NaN
2    7  25.0

Answer 2

Another option with stack:

pd.DataFrame.from_records(
    df.stack().index.swaplevel(),
    columns=['X', 'Y'])

Output:

    X   Y
0  22   1
1   7  25