标签归档:space

如何在Python中检查文本是否为“空”(空格,制表符,换行符)?

问题:如何在Python中检查文本是否为“空”(空格,制表符,换行符)?

如何在Python中测试字符串是否为空?

例如,

"<space><space><space>" 是空的,所以是

"<space><tab><space><newline><space>",也是

"<newline><newline><newline><tab><newline>"

How can I test if a string contains only whitespace?

Example strings:

  • " " (space, space, space)

  • " \t \n " (space, tab, space, newline, space)

  • "\n\n\n\t\n" (newline, newline, newline, tab, newline)


回答 0

yourString.isspace()

“如果字符串中只有空格字符并且至少有一个字符,则返回true,否则返回false。”

结合特殊情况处理空字符串。

或者,您可以使用

strippedString = yourString.strip()

然后检查strippedString是否为空。

Use the str.isspace() method:

Return True if there are only whitespace characters in the string and there is at least one character, False otherwise.

A character is whitespace if in the Unicode character database (see unicodedata), either its general category is Zs (“Separator, space”), or its bidirectional class is one of WS, B, or S.

Combine that with a special case for handling the empty string.

Alternatively, you could use str.strip() and check if the result is empty.


回答 1

>>> tests = ['foo', ' ', '\r\n\t', '', None]
>>> [bool(not s or s.isspace()) for s in tests]
[False, True, True, True, True]
>>>
>>> tests = ['foo', ' ', '\r\n\t', '', None]
>>> [not s or s.isspace() for s in tests]
[False, True, True, True, True]

回答 2

您要使用的isspace()方法

海峡 isspace()

如果字符串中只有空格字符并且至少有一个字符,则返回true,否则返回false。

这是在每个字符串对象上定义的。这是您的特定用例的用法示例:

if aStr and (not aStr.isspace()):
    print aStr

You want to use the isspace() method

str.isspace()

Return true if there are only whitespace characters in the string and there is at least one character, false otherwise.

That’s defined on every string object. Here it is an usage example for your specific use case:

if aStr and (not aStr.isspace()):
    print aStr

回答 3

You can use the str.isspace() method.


回答 4

对于那些希望像Apache StringUtils.isBlank或Guava Strings.isNullOrEmpty这样的行为的用户:

if mystring and mystring.strip():
    print "not blank string"
else:
    print "blank string"

for those who expect a behaviour like the apache StringUtils.isBlank or Guava Strings.isNullOrEmpty :

if mystring and mystring.strip():
    print "not blank string"
else:
    print "blank string"

回答 5

检查split()方法给定的列表的长度。

if len(your_string.split()==0:
     print("yes")

或者将strip()方法的输出与null进行比较。

if your_string.strip() == '':
     print("yes")

Check the length of the list given by of split() method.

if len(your_string.split()==0:
     print("yes")

Or Compare output of strip() method with null.

if your_string.strip() == '':
     print("yes")

回答 6

这是在所有情况下都适用的答案:

def is_empty(s):
    "Check whether a string is empty"
    return not s or not s.strip()

如果变量为None,它将在处停止not s并且不再进行评估(因为not None == True)。显然,该strip()方法可以处理tab,换行符等常见情况。

Here is an answer that should work in all cases:

def is_empty(s):
    "Check whether a string is empty"
    return not s or not s.strip()

If the variable is None, it will stop at not sand not evaluate further (since not None == True). Apparently, the strip()method takes care of the usual cases of tab, newline, etc.


回答 7

我假设在您的情况下,空字符串是真正为空的字符串或包含所有空白的字符串。

if(str.strip()):
    print("string is not empty")
else:
    print("string is empty")

请注意,这不会检查 None

I’m assuming in your scenario, an empty string is a string that is truly empty or one that contains all white space.

if(str.strip()):
    print("string is not empty")
else:
    print("string is empty")

Note this does not check for None


回答 8

我使用以下内容:

if str and not str.isspace():
  print('not null and not empty nor whitespace')
else:
  print('null or empty or whitespace')

I used following:

if str and not str.isspace():
  print('not null and not empty nor whitespace')
else:
  print('null or empty or whitespace')

回答 9

检查字符串只是空格还是换行符

使用这个简单的代码

mystr = "      \n  \r  \t   "
if not mystr.strip(): # The String Is Only Spaces!
    print("\n[!] Invalid String !!!")
    exit(1)
mystr = mystr.strip()
print("\n[*] Your String Is: "+mystr)

To check if a string is just a spaces or newline

Use this simple code

mystr = "      \n  \r  \t   "
if not mystr.strip(): # The String Is Only Spaces!
    print("\n[!] Invalid String !!!")
    exit(1)
mystr = mystr.strip()
print("\n[*] Your String Is: "+mystr)

回答 10

与c#字符串静态方法类似isNullOrWhiteSpace。

def isNullOrWhiteSpace(str):
  """Indicates whether the specified string is null or empty string.
     Returns: True if the str parameter is null, an empty string ("") or contains 
     whitespace. Returns false otherwise."""
  if (str is None) or (str == "") or (str.isspace()):
    return True
  return False

isNullOrWhiteSpace(None) -> True // None equals null in c#, java, php
isNullOrWhiteSpace("")   -> True
isNullOrWhiteSpace(" ")  -> True

Resemblence with c# string static method isNullOrWhiteSpace.

def isNullOrWhiteSpace(str):
  """Indicates whether the specified string is null or empty string.
     Returns: True if the str parameter is null, an empty string ("") or contains 
     whitespace. Returns false otherwise."""
  if (str is None) or (str == "") or (str.isspace()):
    return True
  return False

isNullOrWhiteSpace(None) -> True // None equals null in c#, java, php
isNullOrWhiteSpace("")   -> True
isNullOrWhiteSpace(" ")  -> True