Converting a column within pandas dataframe from int to string

Question

I have a dataframe in pandas with mixed int and str data columns. I want to concatenate first the columns within the dataframe. To do that I have to convert an int column to str. I've tried to do as follows:

mtrx['X.3'] = mtrx.to_string(columns = ['X.3']) 

or

mtrx['X.3'] = mtrx['X.3'].astype(str) 

but in both cases it's not working and I'm getting an error saying "cannot concatenate 'str' and 'int' objects". Concatenating two str columns is working perfectly fine.

Answer 1

In [16]: df = DataFrame(np.arange(10).reshape(5,2),columns=list('AB'))  In [17]: df Out[17]:     A  B 0  0  1 1  2  3 2  4  5 3  6  7 4  8  9  In [18]: df.dtypes Out[18]:  A    int64 B    int64 dtype: object 

---

Convert a series

In [19]: df['A'].apply(str) Out[19]:  0    0 1    2 2    4 3    6 4    8 Name: A, dtype: object  In [20]: df['A'].apply(str)[0] Out[20]: '0' 

Don't forget to assign the result back:

df['A'] = df['A'].apply(str) 

---

Convert the whole frame

In [21]: df.applymap(str) Out[21]:     A  B 0  0  1 1  2  3 2  4  5 3  6  7 4  8  9  In [22]: df.applymap(str).iloc[0,0] Out[22]: '0' 

df = df.applymap(str) 

Answer 2

Change data type of DataFrame column:

To int:

df.column_name = df.column_name.astype(np.int64)

To str:

df.column_name = df.column_name.astype(str)