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import pandas
import random
filename = "data.txt"
n = sum(1 for line in open(filename)) - 1 #number of records in file (excludes header)
s = 10000 #desired sample size
skip = sorted(random.sample(range(1,n+1),n-s)) #the 0-indexed header will not be included in the skip list
df = pandas.read_csv(filename, skiprows=skip)
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>>> df['num_legs'].sample(n=3, random_state=1)
fish 0
spider 8
falcon 2
Name: num_legs, dtype: int64
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# Extract 10% of your dataframe
df.sample(frac=0.1, replace=True, random_state=1)
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import pandas
import random
n = 1000000 #number of records in file
s = 10000 #desired sample size
filename = "data.txt"
skip = sorted(random.sample(range(n),n-s))
df = pandas.read_csv(filename, skiprows=skip)
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>>> df = pd.DataFrame({'num_legs': [2, 4, 8, 0],
'num_wings': [2, 0, 0, 0],
'num_specimen_seen': [10, 2, 1, 8]},
index=['falcon', 'dog', 'spider', 'fish'])
>>> df
num_legs num_wings num_specimen_seen
falcon 2 2 10
dog 4 0 2
spider 8 0 1
fish 0 0 8