Question

我是Python编程的新手，我写了一个模块＆＃34;建议＆＃34;：

from math import sqrt

# A dictionary of movie critics and their ratings of a small set of movies
critics = {
    'Lisa Rose': {
        'Lady in the Water': 2.5,
        'Snakes on a Plane': 3.5,
        'Just My Luck': 3.0,
        'Superman Returns': 3.5,
        'You, Me and Dupree': 2.5,
        'The Night Listener': 3.0},
    'Gene Seymour': {
        'Lady in the Water': 3.0,
        'Snakes on a Plane': 3.5,
        'Just My Luck': 1.5,
        'Superman Returns': 5.0,
        'You, Me and Dupree': 3.5,
        'The Night Listener': 3.0},
    'Michael Phillips': {
        'Lady in the Water': 2.5,
        'Snakes on a Plane': 3.0,
        'Superman Returns': 3.5,
        'The Night Listener': 4.0},
    'Claudia Puig': {
        'Snakes on a Plane': 3.5,
        'Just My Luck': 3.0,
        'Superman Returns': 4.0,
        'You, Me and Dupree': 2.5,
        'The Night Listener': 4.5},
    'Mick LaSelle': {
        'Lady in the Water': 3.0,
        'Snakes on a Plane': 4.0,
        'Just My Luck': 2.0,
        'Superman Returns': 3.0,
        'You, Me and Dupree': 2.0,
        'The Night Listener': 3.0},
    'Jack Matthews': {
        'Lady in the Water': 3.0,
        'Snakes on a Plane': 4.0,
        'Superman Returns': 5.0,
        'You, Me and Dupree': 3.5,
        'The Night Listener': 3.0},
    'Toby': {
        'Snakes on a Plane': 4.5,
        'You, Me and Dupree': 1.0,
        'Superman Returns': 4.0}
}

# Returns a distance-based similarity score for person1 and person2
def sim_distance(prefs, person1, person2):
    # Get the list of shared_items
    si = {}
    for item in prefs[person1]:
        if item in prefs[person2]:
            si[item] = 1
    # if they have no ratings in common, return 0
    if len(si) == 0:
        return 0
    # Add up the squares of all the differences
    sum_of_squares = sum([pow(prefs[person1][item] - prefs[person2] [item], 2)
                          for item in prefs[person1]
                          if item in prefs[person2]])
    return 1 / (1 + sum_of_squares)

每当我运行此模块时，我都会遇到此错误：

Python 2.7.10 (default, May 23 2015, 09:40:32)
[MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> reload(recommendations)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'recommendations' is not defined
>>>

recommendations.py也无效。

事实上每当我尝试调用我的函数sim_distance时生成错误，sim_distance未定义。

Answer 1

我为您格式化了代码。它现在有效。如果将sim_distance函数放在名为recommendations.py的文件中，那么您应该能够导入它。我没有检查你的代码是否正在产生正确的输出......

# Returns a distance-based similarity score for person1 and person2
def sim_distance(prefs, person1, person2):
    # Get the list of shared_items
    si = {}
    for item in prefs[person1]:
        if item in prefs[person2]:
            si[item] = 1
    # if they have no ratings in common, return 0
    if len(si) == 0:
        return 0
    # Add up the squares of all the differences
    sum_of_squares = sum([
        pow(prefs[person1][item] - prefs[person2][item], 2)
        for item in prefs[person1] if item in prefs[person2]])
    return 1 / (1 + sum_of_squares)

并运行

from recommendations import sim_distance
# A dictionary of movie critics and their ratings of a small
# set of movies
critics = {
    'Lisa Rose': {
        'Lady in the Water': 2.5,
        'Snakes on a Plane': 3.5,
        'Just My Luck': 3.0,
        'Superman Returns': 3.5,
        'You, Me and Dupree': 2.5,
        'The Night Listener': 3.0},
    'Gene Seymour': {
        'Lady in the Water': 3.0,
        'Snakes on a Plane': 3.5,
        'Just My Luck': 1.5,
        'Superman Returns': 5.0,
        'You, Me and Dupree': 3.5,
        'The Night Listener': 3.0},
    'Michael Phillips': {
        'Lady in the Water': 2.5,
        'Snakes on a Plane': 3.0,
        'Superman Returns': 3.5,
        'The Night Listener': 4.0},
    'Claudia Puig': {
        'Snakes on a Plane': 3.5,
        'Just My Luck': 3.0,
        'Superman Returns': 4.0,
        'You, Me and Dupree': 2.5,
        'The Night Listener': 4.5},
    'Mick LaSelle': {
        'Lady in the Water': 3.0,
        'Snakes on a Plane': 4.0,
        'Just My Luck': 2.0,
        'Superman Returns': 3.0,
        'You, Me and Dupree': 2.0,
        'The Night Listener': 3.0},
    'Jack Matthews': {
        'Lady in the Water': 3.0,
        'Snakes on a Plane': 4.0,
        'Superman Returns': 5.0,
        'You, Me and Dupree': 3.5,
        'The Night Listener': 3.0},
    'Toby': {
        'Snakes on a Plane': 4.5,
        'You, Me and Dupree': 1.0,
        'Superman Returns': 4.0}
}

print(sim_distance(critics, "Lisa Rose", "Gene Seymour"))

Answer 2

您的代码存在很多问题。主要问题是缩进。你似乎随意缩进你的代码，python但是，要求一个非常严格的缩进制度。 You can read more about it here

我还没有仔细查看你的代码，但是在我修复了缩进后它没有运行。

然而，我期望你的第一个问题是，你忘了首先导入你的模块，如下：

>>> import recommendations

无法加载Python模块

2 个答案: