如何将字符串分割为字符列表?Str.split不起作用。
"foobar" → ['f', 'o', 'o', 'b', 'a', 'r']
如何将字符串分割为字符列表?Str.split不起作用。
"foobar" → ['f', 'o', 'o', 'b', 'a', 'r']
当前回答
下面是一个很好的脚本,可以帮助你找到最有效的方法:
import timeit
from itertools import chain
string = "thisisthestringthatwewanttosplitintoalist"
def getCharList(str):
return list(str)
def getCharListComp(str):
return [char for char in str]
def getCharListMap(str):
return list(map(lambda c: c, str))
def getCharListForLoop(str):
list = []
for c in str:
list.append(c)
def getCharListUnpack(str):
return [*str]
def getCharListExtend(str):
list = []
return list.extend(str)
def getCharListChain(str):
return chain(str)
time_list = timeit.timeit(stmt='getCharList(string)', globals=globals(), number=1)
time_listcomp = timeit.timeit(stmt='getCharListComp(string)', globals=globals(), number=1)
time_listmap = timeit.timeit(stmt='getCharListMap(string)', globals=globals(), number=1)
time_listforloop = timeit.timeit(stmt='getCharListForLoop(string)', globals=globals(), number=1)
time_listunpack = timeit.timeit(stmt='getCharListUnpack(string)', globals=globals(), number=1)
time_listextend = timeit.timeit(stmt='getCharListExtend(string)', globals=globals(), number=1)
time_listchain = timeit.timeit(stmt='getCharListChain(string)', globals=globals(), number=1)
print(f"Execution time using list constructor is {time_list} seconds")
print(f"Execution time using list comprehension is {time_listcomp} seconds")
print(f"Execution time using map is {time_listmap} seconds")
print(f"Execution time using for loop is {time_listforloop} seconds")
print(f"Execution time using unpacking is {time_listunpack} seconds")
print(f"Execution time using extend is {time_listextend} seconds")
print(f"Execution time using chain is {time_listchain} seconds")
其他回答
使用列表构造函数:
>>> list("foobar")
['f', 'o', 'o', 'b', 'a', 'r']
List使用通过迭代输入iterable获得的项构建一个新列表。字符串是一个可迭代对象——在每个迭代步骤中迭代它会产生一个单独的字符。
下面是一个很好的脚本,可以帮助你找到最有效的方法:
import timeit
from itertools import chain
string = "thisisthestringthatwewanttosplitintoalist"
def getCharList(str):
return list(str)
def getCharListComp(str):
return [char for char in str]
def getCharListMap(str):
return list(map(lambda c: c, str))
def getCharListForLoop(str):
list = []
for c in str:
list.append(c)
def getCharListUnpack(str):
return [*str]
def getCharListExtend(str):
list = []
return list.extend(str)
def getCharListChain(str):
return chain(str)
time_list = timeit.timeit(stmt='getCharList(string)', globals=globals(), number=1)
time_listcomp = timeit.timeit(stmt='getCharListComp(string)', globals=globals(), number=1)
time_listmap = timeit.timeit(stmt='getCharListMap(string)', globals=globals(), number=1)
time_listforloop = timeit.timeit(stmt='getCharListForLoop(string)', globals=globals(), number=1)
time_listunpack = timeit.timeit(stmt='getCharListUnpack(string)', globals=globals(), number=1)
time_listextend = timeit.timeit(stmt='getCharListExtend(string)', globals=globals(), number=1)
time_listchain = timeit.timeit(stmt='getCharListChain(string)', globals=globals(), number=1)
print(f"Execution time using list constructor is {time_list} seconds")
print(f"Execution time using list comprehension is {time_listcomp} seconds")
print(f"Execution time using map is {time_listmap} seconds")
print(f"Execution time using for loop is {time_listforloop} seconds")
print(f"Execution time using unpacking is {time_listunpack} seconds")
print(f"Execution time using extend is {time_listextend} seconds")
print(f"Execution time using chain is {time_listchain} seconds")
将字符串传递给list()
s = "mystring"
l = list(s)
print l
如果希望只读访问字符串,可以直接使用数组表示法。
Python 2.7.6 (default, Mar 22 2014, 22:59:38)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> t = 'my string'
>>> t[1]
'y'
对于不使用regexp的测试可能很有用。 字符串是否包含结束换行符?
>>> t[-1] == '\n'
False
>>> t = 'my string\n'
>>> t[-1] == '\n'
True
我探索了另外两种方法来完成这项任务。它可能对某人有帮助。
第一个很简单:
In [25]: a = []
In [26]: s = 'foobar'
In [27]: a += s
In [28]: a
Out[28]: ['f', 'o', 'o', 'b', 'a', 'r']
第二个使用map和函数。它可能适用于更复杂的任务:
In [36]: s = 'foobar12'
In [37]: a = map(lambda c: c, s)
In [38]: a
Out[38]: ['f', 'o', 'o', 'b', 'a', 'r', '1', '2']
例如
# isdigit, isspace or another facilities such as regexp may be used
In [40]: a = map(lambda c: c if c.isalpha() else '', s)
In [41]: a
Out[41]: ['f', 'o', 'o', 'b', 'a', 'r', '', '']
有关更多方法,请参阅python文档