DataFrame.sample(n=None, frac=None, replace=False, weights=None, random_state=None, axis=None)[source]
n : int, optional
Number of items from axis to return. Cannot be used with frac. Default = 1 if frac = None.
frac : float, optional
Fraction of axis items to return. Cannot be used with n.
replace : boolean, optional
Sample with or without replacement. Default = False.
weights : str or ndarray-like, optional
Default ‘None’ results in equal probability weighting. If passed a Series, will align with target object on index. Index values in weights not found in sampled object will be ignored and index values in sampled object not in weights will be assigned weights of zero. If called on a DataFrame, will accept the name of a column when axis = 0. Unless weights are a Series, weights must be same length as axis being sampled. If weights do not sum to 1, they will be normalized to sum to 1. Missing values in the weights column will be treated as zero. inf and -inf values not allowed.
random_state : int or numpy.random.RandomState, optional
Seed for the random number generator (if int), or numpy RandomState object.
axis : int or string, optional
Axis to sample. Accepts axis number or name. Default is stat axis for given data type (0 for Series and DataFrames, 1 for Panels).
Axis参数的意思是，从哪个维度取样。如axis = 0，即从row中取样。