如何在Python中编写“标签”？

Let’s say I have a file. How do I write “hello” TAB “alex”?

This is the code:

f = open(filename, 'w')
f.write("hello\talex")

The \t inside the string is the escape sequence for the horizontal tabulation.

The Python reference manual includes several string literals that can be used in a string. These special sequences of characters are replaced by the intended meaning of the escape sequence.

Here is a table of some of the more useful escape sequences and a description of the output from them.

Escape Sequence       Meaning
\t                    Tab
\\                    Inserts a back slash (\)
\'                    Inserts a single quote (')
\"                    Inserts a double quote (")
\n                    Inserts a ASCII Linefeed (a new line)

Basic Example

If i wanted to print some data points separated by a tab space I could print this string.

DataString = "0\t12\t24"
print (DataString)

Returns

0    12    24

Example for Lists

Here is another example where we are printing the items of list and we want to sperate the items by a TAB.

DataPoints = [0,12,24]
print (str(DataPoints[0]) + "\t" + str(DataPoints[1]) + "\t" + str(DataPoints[2]))

Returns

0    12    24

Raw Strings

Note that raw strings (a string which include a prefix “r”), string literals will be ignored. This allows these special sequences of characters to be included in strings without being changed.

DataString = r"0\t12\t24"
print (DataString)

Returns

0\t12\t24

Which maybe an undesired output

String Lengths

It should also be noted that string literals are only one character in length.

DataString = "0\t12\t24"
print (len(DataString))

Returns

7

The raw string has a length of 9.

You can use \t in a string literal:

"hello\talex"

It’s usually \t in command-line interfaces, which will convert the char \t into the whitespace tab character.

For example, hello\talex -> hello--->alex.

As it wasn’t mentioned in any answers, just in case you want to align and space your text, you can use the string format features. (above python 2.5) Of course \t is actually a TAB token whereas the described method generates spaces.

Example:

print "{0:30} {1}".format("hi", "yes")
> hi                             yes

Another Example, left aligned:

print("{0:<10} {1:<10} {2:<10}".format(1.0, 2.2, 4.4))
>1.0        2.2        4.4 

Here are some more exotic Python 3 ways to get “hello” TAB “alex” (tested with Python 3.6.10):

"hello\N{TAB}alex"

"hello\N{tab}alex"

"hello\N{TaB}alex"

"hello\N{HT}alex"

"hello\N{CHARACTER TABULATION}alex"

"hello\N{HORIZONTAL TABULATION}alex"

"hello\x09alex"

"hello\u0009alex"

"hello\U00000009alex"

Actually, instead of using an escape sequence, it is possible to insert tab symbol directly into the string literal. Here is the code with a tabulation character to copy and try:

"hello alex"

If the tab in the string above won’t be lost anywhere during copying the string then “print(repr(< string from above >)” should print ‘hello\talex’.

See respective Python documentation for reference.