Apply Python lambda : if condition giving syntax error

Question

This is my data set

fake_abalone2

   Sex   Length  Diameter  Height   Whole  Shucked  Viscera  Shell  Rings
                                    Weight  Weight  Weight  Weight
0   M    0.455    0.365    0.095    0.5140  0.2245  0.1010  0.1500  15
1   M    0.350    0.265    0.090    0.2255  0.0995  0.0485  0.0700  7
2   F    0.530    0.420    0.135    0.6770  0.2565  0.1415  0.2100  9
3   M    0.440    0.365    0.125    0.5160  0.2155  0.1140  0.1550  10
4   K    0.330    0.255    0.080    0.2050  0.0895  0.0395  0.0550  7
5   K    0.425    0.300    0.095    0.3515  0.1410  0.0775  0.1200  8

Getting syntax error while using the following method. Please help me out. I want the value in "sex" table to change depending on "Rings" table.If "Rings" value is less than 10 the corresponding "sex" value should be changed to 'K'.Otherwise, no change should be made in "Sex" table.

 fake_abalone2["sex"]=fake_abalone2["Rings"].apply(lambda x:"K" if x<10)

File "", line 1 fake_abalone2["sex"]=fake_abalone2["Rings"].apply(lambda x:"K" if x<10)

SyntaxError: invalid syntax

Answer 1

You can use Python numpy instead of lambda function.

Import python numpy using import numpy as np

then you can use the following method to replace the string.

fake_abalone2['Sex'] = np.where(fake_abalone2['Rings']<10, 'K', fake_abalone2['Sex'])