Python 2to3 无法将 Python 2 代码转换为 Python 3

在使用 2to3 将 Python 2 代码转换为 Python 3 时，遇到文件无法转换的问题。具体表现为：

• 运行 2to3 命令时，提示「RefactoringTool: No files need to be modified」，说明没有文件需要被修改。
• 检查了源文件，确定其为 Python 2 代码，并且包含需要转换的 Python 2 语法。

2、解决方案

经过进一步排查，发现问题出在 Python 的版本上。

• 2to3 工具是 Python 3 中的模块，用于将 Python 2 代码转换为 Python 3 代码。

• 在 MacOS 系统上，Python 2 和 Python 3 共存，并分别安装在不同的目录中。

• 在命令行中运行 2to3 时，如果未指定 Python 版本，则系统会默认使用系统默认的 Python 版本。

• 在我的 MacOS 系统中，系统默认的 Python 版本是 Python 2，因此 2to3 工具使用的是 Python 2 版本。

• 而 Python 2 版本的 2to3 工具不支持将 Python 2 代码转换为 Python 3 代码，因此出现「RefactoringTool: No files need to be modified」的提示。

为了解决问题，需要使用 Python 3 版本的 2to3 工具来转换 Python 2 代码。

• 在 MacOS 系统中，可以通过以下命令来切换到 Python 3 版本的 2to3 工具：

$ python3 -m 2to3

• 切换到 Python 3 版本的 2to3 工具后，再运行 2to3 命令即可将 Python 2 代码转换为 Python 3 代码。

$ python3 -m 2to3 /Users/Nimbuz/Documents/python31/Excercise\ 1/time3.py

以下是转换后的 Python 3 代码：

# handling date/time data
# Python23 tested   vegaseat   3/6/2005

import time

print("List the functions within module time:")
for funk in dir(time):
  print(funk)

print(time.time(), "seconds since 1/1/1970 00:00:00")
print(time.time() / (60 * 60 * 24), "days since 1/1/1970")

# time.clock() gives wallclock seconds, accuracy better than 1 ms
# time.clock() is for windows, time.time() is more portable
print("Using time.clock() = ", time.clock(), "seconds since first call to clock()")
print("\nTiming a 1 million loop 'for loop' ...")
start = time.clock()
for x in range(1000000):
  y = x  # do something
end = time.clock()
print("Time elapsed = ", end - start, "seconds")

# create a tuple of local time data
time_here = time.localtime()
print("\nA tuple of local date/time data using time.localtime():")
print("(year,month,day,hour,min,sec,weekday(Monday=0),yearday,dls-flag)")
print(time_here)

# extract a more readable date/time from the tuple
# eg.  Sat Mar 05 22:51:55 2005
print("\nUsing time.asctime(time.localtime()):", time.asctime(time.localtime()))
# the same results
print("\nUsing time.ctime(time.time()):", time.ctime(time.time()))
print("\nOr using time.ctime():", time.ctime())

print("\nUsing strftime():")
print("Day and Date:", time.strftime("%a %m/%d/%y", time.localtime()))
print("Day, Date   :", time.strftime("%A, %B %d, %Y", time.localtime()))
print("Time (12hr) :", time.strftime("%I:%M:%S %p", time.localtime()))
print("Time (24hr) :", time.strftime("%H:%M:%S", time.localtime()))
print("DayMonthYear:", time.strftime("%d%b%Y", time.localtime()))

print()

print("Start a line with this date-time stamp and it will sort:",
      time.strftime("%Y/%m/%d %H:%M:%S", time.localtime()))

print()


def get_day_of_week(date_string):
  # day of week (Monday = 0) of a given month/day/year
  t1 = time.strptime(date_string, "%m/%d/%Y")
  # year in time_struct t1 can not go below 1970 (start of epoch)!
  t2 = time.mktime(t1)
  return time.localtime(t2)[6]


Weekday = ['Monday', 'Tuesday', 'Wednesday', 'Thursday',
           'Friday', 'Saturday', 'Sunday']

# sorry about the limitations, stay above 01/01/1970
# more exactly 01/01/1970 at 0 UT (midnight Greenwich, England)
print("11/12/1970 was a", Weekday[get_day_of_week("11/12/1970")])

print()

print("Calculate difference between two times (12 hour format) of a day:")
time1 = input("Enter first time (format 11:25:00AM or 03:15:30PM): ")
# pick some plausible date
time_string1 = "03/06/05 " + time1
# create a time tuple from this time string format eg. 03/06/05 11:22:00AM
time_tuple1 = time.strptime(time_string1, "%m/%d/%y %I:%M:%S%p")

# print timeTuple1   # test eg. (2005, 3, 6, 11, 22, 0, 5, 91, -1)

time2 = input("Enter second time (format 11:25:00AM or 03:15:30PM): ")
# use same date to stay in same day
time_string2 = "03/06/05 " + time2
time_tuple2 = time.strptime(time_string2, "%m/%d/%y %I:%M:%S%p")

# mktime() gives seconds since epoch 1/1/1970 00:00:00
time_difference = time.mktime(time_tuple2) - time.mktime(time_tuple1)
# print type(time_difference)  # test <type 'float'>
print("Time difference = %d seconds" % int(time_difference))
print("Time difference = %0.1f minutes" % (time_difference / 60.0))
print("Time difference = %0.2f hours" % (time_difference / (60.0 * 60)))

print()

print("Wait one and a half seconds!")
time.sleep(1.5)
print("The end!")