Python程序不给出输出

Question

I have been trying to write out a problem birthday.py. Suppose that people enter an empty room until; a pair of people share a birthday. On average, how many people will have to enter before there is a match? Write a program birthday.py that accepts trials (int) as command-line argument, runs trials experiments to estimate this quantity — each experiment involves sampling individuals until a pair of them share a birthday, and writes the value to standard output. My trouble has been getting an output. If I enter 1000 in the command terminal 24 should be the output but it doesn't give anything.

DAYS_PER_YEAR = 365
    
    # Accept trials (int) as command-line argument.
    trials = int(sys.argv[1])
    
    # Set count, denoting the total number of individuals sampled across the trials number of
    # experiments, to 0.
    total = 0
    
    for i in range(trials):
        # Perform trials number of experiments, where each experiment involves sampling individuals
        # until a pair of them share a birthday...
    
        # Setup a 1D list birthdaysSeen of DAYS_PER_YEAR Booleans, all set to False by default. This
        # list will keep track of the birthdays encountered in this experiment.
        birthdaysSeen = stdarray.create1D(DAYS_PER_YEAR, False)
        while True:
            # Sample individuals until match
            n = stdrandom.uniformInt(0, 364)
            # Increment count by 1.
            total += 1
    
            # Set birthday to a random integer from [0, DAYS_PER_YEAR).
            birthday = stdrandom.uniformInt(0, DAYS_PER_YEAR)
    
            if birthdaysSeen[birthday]:
                # If birthday has been encountered, abort this experiment, ie, break.
                break
        else:
            # Record the fact that we are seeing this birthday for the first time.
            birthdaysSeen[birthday] = True
    # Write to standard output the average number of people that must be sampled before a match,
    # as an int.
    stdio.writeln(count // trials)

Answer 1

in Python, you can do

print(count // trials)

for almost any data structure as nearly all of them have a __repr__() or an __str()__ method defined.

And since count and trials should be pure numerical data types, print() should do the trick

Answer 2

Your while loop has an else, which turns it into an infinite loop. Tab this line in to match up with the if instead of the while :

    else:
        # Record the fact that we are seeing this birthday for the first time.
        birthdaysSeen[birthday] = True

Also, your print at the end should be total // trials not count // trials

Answer 3

我建议使用print()而不是stdio.writeln()

Answer 4

stdio.writeln is not a built in Python function. Use print or import stdout from the sys module and write to it like this:

from sys import stdout

stdout.write(count // trials + "\n")

The \\n is a newline. print automatically appends a newline. sys.stdout.write does not.