pandas count occurrences in column code example

Example 1: pandas count occurrences in column

# Basic syntax:
df['column'].value_counts()

# Get normalized counts:
df['column'].value_counts(normalize=True)

# Example usage:
# Make dataframe
import pandas as pd
df = pd.DataFrame(np.array([[1, 2, 3], [4, 5, 6], [7, 5, 9]]), 
                  columns=['a', 'b', 'c'])

print(df)
   a  b  c
0  1  2  3
1  4  5  6
2  7  5  9

df['b'].value_counts() # Returns:
5    2 # 5 appears twice in column 'b'
2    1

df['b'].value_counts(normalize=True) # Returns:
5    0.666667 # 5 accounts for 2/3 of the entries in column 'b'
2    0.333333

Example 2: pandas count specific value in column

(df[education]=='9th').sum()

Example 3: pandas count all values in whole dataframe

df.stack().value_counts()

Example 4: count specific instances in a columb in pandas

df.describe(include=['O']) # give count of unieque categorical

Example 5: python - count number of occurence in a column

print df
  col1 education
0    a       9th
1    b       9th
2    c       8th

len(df[df['education'] == '9th'])

Example 6: pandas count occurrences of certain value in row

print df
  col1 education
0    a       9th
1    b       9th
2    c       8th

print df.education == '9th'
0     True
1     True
2    False
Name: education, dtype: bool

print df[df.education == '9th']
  col1 education
0    a       9th
1    b       9th

print df[df.education == '9th'].shape[0]
2
print len(df[df['education'] == '9th'])
2