I am new to Python. I am trying to add a randomly generated variable to an already existing dataframe. I get an error message, but can't figure out why.
import pandas as pd
import numpy as np
data=[10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
df=pd.DataFrame(data, columns=['age'])
# Add income:
income_5 = np.random.randint(low=0, high=4, size=(nrows(df,))+1
df['income5'] = income_5
What am I doing wrong?
After changing size=(nrows(df,) to size=(len(df),) it works, so:
import pandas as pd
import numpy as np
data=[10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
df=pd.DataFrame(data, columns=['age'])
# Add income:
income_5 = np.random.randint(low=0, high=4, size=(len(df),))+1
df['income5'] = income_5
The correct syntax would be size=df.shape[0] or size=len(df):
income_5 = np.random.randint(low=0, high=4, size=df.shape[0])
df['income5'] = income_5
Example:
age income5
0 10 0
1 20 3
2 30 0
3 40 3
4 50 0
5 60 3
6 70 0
7 80 0
8 90 2
9 100 1
NB. You don't need the intermediate variable:
df['income5'] = np.random.randint(low=0, high=4, size=df.shape[0])
