python - 我怎样才能在 python 中停止循环迭代

Question

我想在我的代码中执行几行后停止 for 循环

cursor.execute("select score*100 from daily_stats1 where  user_id=102")
rows = cursor.fetchall()
# Convert query to objects of key-value pairs
lastweek1 = list()
i = 0
for row in rows:
    lastweek1.append(row[i])
    if i == 4:
        break

Answer 1

您从未增加您的i。要么这样做，要么留给 enumerate。此外，根据您的说明，您只想打印 4 行，您最好在循环的顶部进行检查，否则您将打印 5 行:

lastweek1 = list()
for i, row in enumerate(rows):
    if i == 4:
        break
    lastweek1.append(row)

或者您无法将其复杂化 :)。前四整行很简单

lastweek1 = rows[:4]

或者如果它是一个生成器(这很可能)并且您需要具体化它，

lastweek1 = list(rows[:4])