1. Two ways to get a column of another column with max/min values:
a. most_bars_country = flags["name"][flags["bars"].idxmax()]
b. bars_sorted = flags.sort_values("bars", ascending=[0])
most_bars_country = bars_sorted["name"].iloc[0]
2. The way to get the probability of a certain value in a column:
orange_probability = flags[flags["orange"]==1].shape[0]/flags.shape[0]
3. The way to calculate combination by using factorial：
import math
def find_outcome_combinations(N, k): # Calculate the numerator of our formula.
numerator = math.factorial(N) # Calculate the denominator.
denominator = math.factorial(k) * math.factorial(N - k) # Divide them to get the final value.
return numerator / denominator
4.
Statistics and Linear Algebra 6
原文：http://www.cnblogs.com/kingoscar/p/6143510.html