python - How to replace empty cells with 0 and change strings to integers where possible in a pandas dataframe? -

i have dataframe 3000+ columns. many cells in dataframe empty strings (' '). also, have lot of numerical values are strings should integers. wrote 2 functions fill empty cells 0 , possible change value integer, when run them nothing changes dataframe. functions:

def recode_empty_cells(dataframe, list_of_columns):      column in list_of_columns:         dataframe[column].replace(r'\s+', np.nan, regex=true)         dataframe[column].fillna(0)      return dataframe  def change_string_to_int(dataframe, list_of_columns):      dataframe = recode_empty_cells(dataframe, list_of_columns)      column in list_of_columns:         try:             dataframe[column] = dataframe[column].astype(int)         except valueerror:             pass      return dataframe 

note: i'm using try/except statement because columns contain text in form. in advance help.

edit:

thanks got first part working. empty cells have 0s now. code @ moment:

def recode_empty_cells(dataframe, list_of_columns):      column in list_of_columns:         dataframe[column] = dataframe[column].replace(r'\s+', 0, regex=true)      return dataframe  def change_string_to_int(dataframe, list_of_columns):      dataframe = recode_empty_cells(dataframe, list_of_columns)      column in list_of_columns:         try:             dataframe[column] = dataframe[column].astype(int)         except valueerror:             pass      return dataframe 

however, gives me following error: overflowerror: python int large convert c long

you not saving change in function:

def recode_empty_cells(dataframe, list_of_columns):      column in list_of_columns:       dataframe[column] = dataframe[column].replace(r'\s+', np.nan, regex=true)       dataframe[column] = dataframe[column].fillna(0)      return dataframe