Yet another TEXTSCAN question...
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Example string:
s = ['"1","2","3"' 10 '"","2","3"' 10 '"1","","3"' 10 '"1","2",""' 10 '"","",""' 10]
s =
'"1","2","3"
"","2","3"
"1","","3"
"1","2",""
"","",""
'
I want to extract columns as either cellstring or as numbers, using textscan (because it is fast). I can cheat and do this with the following:
t=textscan(strrep(s,'"',''),'%f%f%f','Delimiter',','); [t{:}] %as number
ans =
1 2 3
NaN 2 3
1 NaN 3
1 2 NaN
NaN NaN NaN
t=textscan(strrep(s,'"',''),'%s%s%s','Delimiter',','); [t{:}] %as string
ans =
5×3 cell array
{'1' } {'2' } {'3' }
{0×0 char} {'2' } {'3' }
{'1' } {0×0 char} {'3' }
{'1' } {'2' } {0×0 char}
{0×0 char} {0×0 char} {0×0 char}
But how to do it without strrep? so as to operate on file_id directly..
I have spent hours, thinking I've almost got it, 1 million permutations later no joy.. :'( :'( :'(
回答(2 个)
dpb
2018-5-27
编辑:dpb
2018-5-27
Let textscan do the equivalent strrep for you...
>> fmt1=repmat('%f',1,3);
>> t=cell2mat(textscan(s,fmt1,'delim',',','collectout',1,'whitespace','"'))
t =
1 2 3
NaN 2 3
1 NaN 3
1 2 NaN
NaN NaN NaN
>> fmt2=repmat('%s',1,3);
>> t=textscan(s,fmt2,'delim',',','collectout',1,'whitespace','"')
t =
1×1 cell array
{5×3 cell}
>> t{:}
ans =
5×3 cell array
{'1"' } {'2"' } {'3"' }
{0×0 char} {'2"' } {'3"' }
{'1"' } {0×0 char} {'3"' }
{'1"' } {'2"' } {0×0 char}
{0×0 char} {0×0 char} {0×0 char}
>>
7 个评论
dpb
2018-5-28
+1 Stephen; forgot about '%q'.
Serge, it works to reproduce your suggested/requested output for the strings case; the alternative posted works for numeric.
Jeremy Hughes
2018-5-29
If the numbers are always surrounded by double-quotes, try this,
t = textscan(s,'"%f""%f""%f"','Delimiter',',')
or,
t = textscan(s,'%f%f%f', 'Delimiter',',','Whitespace',' \t"')
There's a lot of knobs in textscan. If you have a file with this kind of data, I suggest:
opts = detectImportOptions(filename)
t = readtable(filename)
HTH,
Jeremy
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