Pandas(Python) : Fill empty cells with with previous row value?

Question

I want to fill empty cells with with previous row value if they start with number. For example, I have

    Text    Text    
    30      Text    Text    
            


        

Answer 1

First, replace your empty cells with NaNs:

df[df[0]==""] = np.NaN

Now, Use ffill():

df.fillna(method='ffill')
#       0
#0  Text
#1    30
#2    30
#3    30
#4    31
#5  Text
#6    31
#7    31
#8    31
#9    32

Answer 2

I think you can first get NaN instead whitespaces:

df.Text = df.Text[df.Text.str.strip() != '']

print (df)
    Text Text.1      
0     30   Text  Text
1    NaN   Text  Text
2    NaN   Text  Text
3     31   Text  Text
4   Text   Text   NaN
5     31   Text  Text
6    NaN   Text  Text
7    NaN   Text  Text
8     32   Text  Text
9   Text   Text   NaN
10   NaN   Text  Text
11   NaN   Text  Text
12   NaN   Text  Text
13   NaN   Text  Text

Then use ffill (same as fillna with parameter ffill), get to_numeric for where for replace NaN if not numeric forward filling NaN, last replace NaN by empty string by fillna:

orig = df.Text.copy()
df.Text = df.Text.ffill()
mask1 = pd.to_numeric(df.Text, errors='coerce')
df.Text = df.Text.where(mask1, orig).fillna('')
print (df)
    Text Text.1      
0     30   Text  Text
1     30   Text  Text
2     30   Text  Text
3     31   Text  Text
4   Text   Text   NaN
5     31   Text  Text
6     31   Text  Text
7     31   Text  Text
8     32   Text  Text
9   Text   Text   NaN
10         Text  Text
11         Text  Text
12         Text  Text
13         Text  Text