根据当前项目和下一项目的值替换列表中的值

I am trying to use the Python code below to output a new list. The output of print (words) should be ['my','name','is','michael','apples','i','like','cars'].

我试图使用下面的Python代码输出一个新的列表。 print(单词)的输出应该是['my','name','is','michael','apples','i','like','cars']。

Right now, print (words) outputs only ['cars']. What am I missing here?

现在,打印(单词)仅输出['cars']。我在这里错过了什么?

a = 'my name is michael and i like cars'
b = a.split()
words = None
for i, j in enumerate(b):
    words = []
    if j == "and" and b[i+1][0] == "i":
        words.append("apples")
    else:
        words.append(j)
print (words)

5 个解决方案

#1

Create words outside the loop, you only see the last word because you keep setting words equal to an empty list each iteration:

在循环外创建单词,您只看到最后一个单词,因为您在每次迭代时都会将单词设置为等于空列表:

words = [] # outside the loop
for i, j in enumerate(b):

If and happens to be the last word you will also get an IndexError. You can set the start index to 1 in enumerate then you don't need to +1 and will avoid any potential error indexing:

如果恰好是最后一个词,你也会得到一个IndexError。您可以在枚举中将起始索引设置为1,然后您不需要+1并且将避免任何潜在的错误索引:

words = []
for i, j in enumerate(b, 1):
    if j == "and" and b[i][0] == "i":

You can put it all in a list comprehension:

你可以把它全部放在列表理解中:

a = 'my name is michael and i like cars'
b = a.split()
words = ["apples" if wrd == "and" and b[i][0] == "i" else wrd for i, wrd in enumerate(b,1)]
print(words)
['my', 'name', 'is', 'michael', 'apples', 'like', 'cars']

You can also avoid indexing using iter and next:

您还可以使用iter和next来避免索引:

a = 'my name is michael and i like cars'
it = iter(a.split())
words = ["apples" if wrd == "and" and next(it," ")[0] == "i" else wrd for wrd in it ]
print(words)
['my', 'name', 'is', 'michael', 'apples', 'like', 'cars']

#2

You have an issue in your loop. Every time you iterate, you reset words to []

您的循环中存在问题。每次迭代时,都会将单词重置为[]

Set the list to [] outside of the for loop, like so:

将列表设置为for循环外的[],如下所示:

words = []
for i, j in enumerate(b):
    if j == "and" and b[i+1][0] == "i":
        words.append("apples")
    else:
        words.append(j)

This should work.

这应该工作。

#3

TigerhawkT3 is correct. To fix your code, instead of initializing words to None, try initializing it as an empty array:

TigerhawkT3是正确的。要修复代码,请尝试将其初始化为空数组,而不是将单词初始化为None:

a = 'my name is michael and i like cars'
b = a.split()
words = []
for i, j in enumerate(b):
    if j == "and" and b[i+1][0] == "i":
        words.append("apples")
    else:
        words.append(j)
print (words)

#4

This should work for you.

这应该适合你。

a = 'my name is michael and i like cars'
b = a.split()
words = []
for x in range(len(b)-1):
    if b[x] == "and" and b[x+1] == "i":
        words.append("apples")
    else:
        words.append(j)
print (words)

#5

I have a more compact method.

我有一个更紧凑的方法。

I think it's more readable and easy to understand. You can refer as below:

我认为它更易读,更容易理解。你可以参考如下:

This is your var I delcare response:

这是你的var I delcare回复:

a = 'my name is michael and i like cars'
b = a.split()
words = []
for i, j in enumerate(b):
    if j == "and" and b[i+1][0] == "i":
        words.append("apples")
    else:
        words.append(j)
print (words)

#1