How do I retrieve the number of columns in a Pandas data frame

Question

How do you programmatically retrieve the number of columns in a pandas dataframe  I was hoping for something like   df num columns

User · Answer

Surprised I haven t seen this yet  so without further ado  here is  df columns size

User · Answer

In order to include the number of row index  quot columns quot  in your total shape I would personally add together the number of columns df columns size with the attribute pd Index nlevels pd MultiIndex nlevels  Set up dummy data import pandas as pd  flat index   pd Index  0  1  2   multi index   pd MultiIndex from tuples    quot a quot   1     quot a quot   2     quot b quot   1   names   quot letter quot    quot id quot     columns     quot cat quot    quot dog quot    quot fish quot    data     1  2  3    4  5  6    7  8  9   flat df   pd DataFrame data  index flat index  columns columns  multi df   pd DataFrame data  index multi index  columns columns     Show data   -----------------   3 columns  4 including the index print flat df      cat  dog  fish id                 0     1    2     3 1     4    5     6 2     7    8     9    -----------------   3 columns  5 including the index print multi df             cat  dog  fish letter id                 a      1     1    2     3        2     4    5     6 b      1     7    8     9  Writing our process as a function  def total ncols df  include index False       ncols   df columns size     if include index is True          ncols    df index nlevels     return ncols  print  quot Ignore the index  quot   print total ncols flat df   total ncols multi df    print  quot Include the index  quot   print total ncols flat df  include index True   total ncols multi df  include index True    This prints  Ignore the index  3 3  Include the index  4 5  If you want to only include the number of indices if the index is a pd MultiIndex  then you can throw in an isinstance check in the defined function  As an alternative  you could use df reset index   columns size to achieve the same result  but this won t be as performant since we re temporarily inserting new columns into the index and making a new index before getting the number of columns

User · Answer

If the variable holding the dataframe is called df  then   len df columns    gives the number of columns   And for those who want the number of rows   len df index    For a tuple containing the number of both rows and columns   df shape

User · Answer

There are multiple option to get column number and column information such as  let s check them   local df   pd DataFrame np random randint 1 12 size  2 6   columns    a   b   c   d   e   f     1  local df shape 1    --  Shape attribute return tuple as  row  amp  columns   0 1      local df info       --  info Method will return detailed information about data frame and it s columns such column count  data type of columns                           Not null value count  memory usage by Data Frame len local df columns  --  columns attribute will return index object of data frame columns  amp  len function will return total available columns  local df head 0     --  head method with parameter 0 will return 1st row of df which actually nothing but header    Assuming number of columns are not more than 10  For loop fun  li count  0 for x in local df      li count  li count   1 print li count

User · Answer

This worked for me len list df

User · Answer

Alternative    df shape 1     df shape 0  is the number of rows

User · Answer

use a regular expression to parse the column count  https   docs python org 3 library re html  buffer   io StringIO   df info buf buffer  s   buffer getvalue   pat re search r quot total s 1  0-9  s 1 column quot  s  print s  phrase pat group 0  value re findall r  0-9    phrase  0  print int value

User · Answer

Like so   import pandas as pd df   pd DataFrame   pear    1 2 3    apple    2 3 4    orange    3 4 5     len df columns  3

User · Answer

df info   function will give you result something like as below   If you are using read csv method of Pandas without sep parameter or sep with       raw data   pd read csv  a1  aa2 aaa3 data csv   raw data info    lt class  pandas core frame DataFrame  gt  RangeIndex  5144 entries  0 to 5143 Columns  145 entries  R fighter to R age

[python] How do I retrieve the number of columns in a Pandas data frame?

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