Question

我有一个清单：

ab = [1, 2, a, b, c]

我做了：

strab = str(ab).

所以strab现在是一个字符串。

我想将该字符串强制转换为列表。

我该怎么做？

Answer 1

最简单，最安全的方法是使用ast.literal_eval()：

import ast

ab = [1, 2, 'a', 'b', 'c']    # a list
strab = str(ab)               # the string representation of a list
strab
=> "[1, 2, 'a', 'b', 'c']"

lst = ast.literal_eval(strab) # convert string representation back to list
lst
=> [1, 2, 'a', 'b', 'c']

ab == lst                     # sanity check: are they equal?
=> True                       # of course they are!

请注意，调用eval()也有效，但it's not safe并且您不应该使用它：

eval(strab)
=> [1, 2, 'a', 'b', 'c']

Answer 2

使用ast包：

import ast
lst = ast.literal_eval(strab)

Answer 3

在使用序列设置numpy数组元素的上下文中，您可以使用内置联接来绕过将其设置为字符串：

og_list_obj = str_list_obj.split("-")

然后在需要时再次使用相同的连接器拆分字符串序列（前提是它没有出现在列表的字符串中）：

with data(t) as ( values ('message'), ('message s'), ('message sag'), ('message sag sag'), ('message sag sage') ) select t as "text", show_trgm(t) as "text trigrams", show_trgm('sage') as "string trigrams", cardinality(array_intersect(show_trgm(t), show_trgm('sage'))) as "common trgms" from data; text | text trigrams | string trigrams | common trgms ------------------+-----------------------------------------------------------+-----------------------------+-------------- message | {" m"," me",age,ess,"ge ",mes,sag,ssa} | {" s"," sa",age,"ge ",sag} | 3 message s | {" m"," s"," me"," s ",age,ess,"ge ",mes,sag,ssa} | {" s"," sa",age,"ge ",sag} | 4 message sag | {" m"," s"," me"," sa","ag ",age,ess,"ge ",mes,sag,ssa} | {" s"," sa",age,"ge ",sag} | 5 message sag sag | {" m"," s"," me"," sa","ag ",age,ess,"ge ",mes,sag,ssa} | {" s"," sa",age,"ge ",sag} | 5 message sag sage | {" m"," s"," me"," sa","ag ",age,ess,"ge ",mes,sag,ssa} | {" s"," sa",age,"ge ",sag} | 5 (5 rows)

如何将字符串转换回列表

3 个答案: