sys.argv會導致索引錯誤

Question

這是我的泊松過程腳本。它導致的問題是錯誤即在第7行（a = float(sys.argv[1])）

IndexError: List index out of range.

我沒有能夠解決它。請幫我解決它。

import random 
import math 
import sys 
import time 

# Expected number of arrivals per unit time. 
a = float(sys.argv[1]) 
# Number of events 
count = int(sys.argv[2]) 

# Function for testing API 
def test_api(): 
    print "Testing API..." 
    # TODO: Make request to the API 

# Make a function iterable, by repeatedly calling it. 
def make_iterable(func, *args): 
    try: 
     while 1: 
      yield func(*args) 
    except: 
     pass 

uni_rand = make_iterable(random.uniform, 0, 1) 

# A generator for inter-arrival times. 
inter_arrival = (-(1./a)*math.log(u) for u in uni_rand) 

# Generate inter-arrival times, then sleep for that long. 
inter_arrival_iter = iter(inter_arrival) 
for i in xrange(count): 
    inter_arrival_seconds = inter_arrival_iter.next() * 3600. 
    print "Sleeping for %f seconds." % inter_arrival_seconds 
    time.sleep(inter_arrival_seconds) 
    test_api() 

Answer 1

您不「修復它」，您將參數傳遞給腳本。

./script.py 1.2 7 

如果要檢查，如果你有足夠的論據事先那麼你需要檢查它的長度（len(sys.argv)）。