China DOS Union

Using for to analyze the content of a certain text. In case the lines separated by spaces in the text are broken and the strings after the spaces are cut off, I see some people use "tokens=*" and some use "delims=", and some people use both. What are the differences in these two usages? I personally understand that the effects should be the same. "tokens=*" means taking all fields, "delims=" means not specifying any delimiter. If there are spaces in the first line of the text to break it, using one of them can make the analyzed string not break, right? Is it that you can use either one according to personal preference, or are there some tips in the usage of these two? I hope the friends who know will tell me, thank you for replying in your busy schedule!

[ Last edited by oilio on 2007-2-8 at 08:51 PM ]

Just try it yourself.

delims refers to the delimiter, and tokens refers to the selected string fragments after splitting.

Take the following code as an example:
FOR /F "eol=; tokens=2,3* delims=," %i in ("a,bc,def,ghij,jklmn") do @echo %i %j %k
Here, Delims is ",", so "a,bc,def,ghij,klmn") is split into 5 segments: a bc def ghij klmn.
tokens=2,3* means to take the 2nd fragment, the 3rd fragment, and all fragments after the 3rd fragment. That is:
%i=bc
%j=def
%k=ghij,klmn (here "*" means that from the 4th fragment onwards, no more splitting is done, all are assigned to %k)
So if you use "tokens=*" in your code, it means no splitting is performed, and the current line is directly assigned to the loop variable.

[ Last edited by lelige on 2007-3-20 at 11:42 PM ]

It can simply give you an example. For example, there is a text a.txt with the following content:
hello world
thank you very
you are very good

These three lines of content
for /f "tokens=*" %a in (a.txt) do @echo %a
hello world
thank you very
you are very good

It can indirectly delete the spaces in front of each line

for /f "delims=" %a in (a.txt) do @echo %a

hello world
thank you very
you are very good

Still the original text, heh heh. You can explore the specific parameters and applications inside by yourself

Thank you, brother upstairs. I seem to have grasped a little bit of the essence.

First, top it, and learn slowly

Learning

After seeing the 3rd floor, I gradually understood, thank you

It is suggested to ban the ID of the person upstairs and delete all their posts.

Originally posted by Climbing at 2007-2-9 21:39:
Just try it yourself.

Helping others improve themselves is beneficial to both others and oneself
@echo off title Usage of "tokens=2 and delims=," in the for command echo. echo Before the bed the bright moon shines, I think frost on the ground it is. Raising my head, I watch the bright moon, lowering my head, I think of home. echo. echo If I want to display all four lines of the poem on the screen using for without any parameters, it can be achieved: echo for /f %%i in (JingYeSi.txt) do echo %%i ECHO 1-1 Before the bed the bright moon shines, 1-2 I think frost on the ground it is, 1-3 Raising my head, I watch the bright moon, 1-4 Lowering my head, I think of home.> JingYeSi.txt ECHO 2-1 Before the bed the bright moon shines, 2-2 I think frost on the ground it is, 2-3 Raising my head, I watch the bright moon, 2-4 Lowering my head, I think of home.>>JingYeSi.txt ECHO 3-1 Before the bed the bright moon shines, 3-2 I think frost on the ground it is, 3-3 Raising my head, I watch the bright moon, 3-4 Lowering my head, I think of home.>>JingYeSi.txt for /f %%i in (JingYeSi.txt) do echo %%i pause>nul echo. ECHO If I only want the sentence "Before the bed the bright moon shines", I need the help of delims: ECHO for /f "delims=，" %%i in (JingYeSi.txt) do echo %%i for /f "delims=，" %%i in (JingYeSi.txt) do echo %%i ECHO delims= followed by a comma means using the comma in the original text as the delimiter (the method of division) to divide the ancient poem into four sections. By default, delims only displays the first section before the delimiter, and the delimiter is usually ignored. pause>nul echo. ECHO To display the verses of other sections, the column extraction command "tokens" is used. ECHO for /f "tokens=2 delims=，" %%i in (JingYeSi.txt) do echo %%i for /f "tokens=2 delims=，" %%i in (JingYeSi.txt) do echo %%i ECHO tokens=2 means the second character set of the object (here, each line) pause>nul

[ Last edited by dosz on 2009-3-7 at 10:51 ]

tokens= When the item is empty, only take the first item,
delims= When the item is empty (default), use spaces and [Tab] as delimiters,

Very good, very powerful, I've learned

I've always been unfamiliar with for, but now I'm a bit closer to it!
THANK ALL!