Merge two or more lines of text into one line with python pandas

I have a txt file like below,

140037|1|TOP SOIL DARK BROWN CLAY RICH ORGANIC|0|0.8
140037|2|MATER SOFT||
140037|3|SANDY CLAY SOFT MOTTLED GREY/ORANGE|0.8|1
140037|4|BROWN <15% SAND GRAINS||
140037|5|CLAY MOTTLED DARK GREY/ORANGE BROWN|1|3
140037|6|SOFT BECOMING FIRM MINOR SILT AND||
140037|7|FINE SAND IN SOME LAYERS||

and want to make it like this.

140037|1|TOP SOIL DARK BROWN CLAY RICH ORGANIC MATER SOFT|0|0.8
140037|2|SANDY CLAY SOFT MOTTLED GREY/ORANGE BROWN <15% SAND GRAINS|0.8|1
140037|3|CLAY MOTTLED DARK GREY/ORANGE BROWN SOFT BECOMING FIRM MINOR SILT AND FINE SAND IN SOME LAYERS|1|3

I am using pandas to read file but not sure how to use merge. Any help will be appreciated.

>Solution :

Use:

#create DataFrame
df = pd.read_csv(file, sep="|", header=None)

#create groups by non missing values in 3,4 columns and aggregate by join and first
df1 = (df.assign(g = df[[3,4]].notna().any(axis=1).cumsum())
        .groupby([0,'g'], as_index=False)
        .agg({2:' '.join, 3:'first', 4:'first'}))

print (df1)
        0  g                                                  2    3    4
0  140037  1   TOP SOIL DARK BROWN CLAY RICH ORGANIC MATER SOFT  0.0  0.8
1  140037  2  SANDY CLAY SOFT MOTTLED GREY/ORANGE BROWN <15%...  0.8  1.0
2  140037  3  CLAY MOTTLED DARK GREY/ORANGE BROWN SOFT BECOM...  1.0  3.0

#write to new file
df1.to_csv(new_file, index=False, header=False, sep='|')