Flutter: Replace particular string after '.jpg' - flutter

I have strings of jpg name
a = '123a.jpg'
b = '456asa.jpg'
c = '789pa.jpg'
Is there a way to replace the final a before .jpg with b?
new_a = '123b.jpg'
new_b = '456asb.jpg'
new_c = '789pb.jpg'

Using a small work arround:
a = a.split('').reversed.join().replaceFirst('a', 'b').split('').reversed.join();

Try
String newa = a.replace("a.", "b.");
Edit. You can also do
newa = a.replaceAll("a$","b");
Here $ means last index

Related

MATLAB filename separation

In filename "name" like '10_m1_m2_const_m1_waves_20_90_m2_waves_90_20_20200312_213048' I need to separate
'10_m1_m2_const_m1_waves_20_90_m2_waves_90_20' from '20200312_213048'
name_sep = split(name,"_");
sep = '_';
name_join=[name_sep{1,1} sep name_sep{2,1} sep .....];
is not working, because a number of "_" are variable.
So I need to move a file:
movefile([confpath,name(without 20200312_213048),'.config'],[name(without 20200312_213048), filesep, name, '.config']);
Do you have any idea? Thank you!
Maybe you can try regexp to find the starting position for the separation:
ind = regexp(name,'_\d+_\d+$');
name1 = name(1:ind-1);
name2 = name(ind+1:end);
such that
name1 = 10_m1_m2_const_m1_waves_20_90_m2_waves_90_20
name2 = 20200312_213048
Or the code below with option tokens:
name_sep = cell2mat(regexp(name,'(.*)_(\d+_\d+$)','tokens','match'));
which gives
name_sep =
{
[1,1] = 10_m1_m2_const_m1_waves_20_90_m2_waves_90_20
[1,2] = 20200312_213048
}
You can use strfind. Either if you have a key that is always present before or after the point where you want to split the name:
nm = '10_m1_m2_const_m1_waves_20_90_m2_waves_90_20_20200312_213048';
key = 'waves_90_20_';
idx = strfind(nm,key) + length(key);
nm(idx:end)
Or if you know how may _ are in the part that you want to have:
idx = strfind(nm,'_');
nm(idx(end-2)+1:end)
In both cases, the result is:
'20_20200312_213048'
As long as the timestamp is always at the end of the string, you can use strfind and count backwards from the end of the string:
name = '10_m1_m2_const_m1_waves_20_90_m2_waves_90_20_20200312_213048';
udscr = strfind(name,'_');
name_date = name(udscr(end-1)+1:end)
name_meta = name(1:udscr(end-1)-1)
name_date =
'20200312_213048'
name_meta =
'10_m1_m2_const_m1_waves_20_90_m2_waves_90_20'

Extract fields from Structure Array to put into another Structure Array

I have a structure array with a large number of fields that I don't care about, so I want to extract the limited number of fields I DO care about and put it into a separate structure array.
For a structure array of size one, I've done this by creating the new array from scratch, for example:
structOld.a = 1;
structOld.b = 2;
structOld.usefulA = 'useful information';
structOld.usefulB = 'more useful information';
structOld.c = 3;
structOld.d = 'words';
keepFields = {'usefulA','usefulB'};
structNew = struct;
for fn = keepFields
structNew.(fn{:}) = structOld.(fn{:});
end
which gives
structNew =
usefulA: 'useful information'
usefulB: 'more useful information'
Is there a more efficient way of doing this? How can I scale up to an structure array (vector) of size N?
N = 50;
structOld(1).a = 1;
structOld(1).b = 2;
structOld(1).usefulA = 500;
structOld(1).usefulB = 'us';
structOld(1).c = 3;
structOld(1).d = 'ef';
structOld(2).a = 4;
structOld(2).b = 5;
structOld(2).usefulA = 501;
structOld(2).usefulB = 'ul';
structOld(2).c = 6;
structOld(2).d = 'in';
structOld(3).a = 7;
structOld(3).b = '8';
structOld(3).usefulA = 504;
structOld(3).usefulB = 'fo';
structOld(3).c = 9;
structOld(3).d = 'rm';
structOld(N).a = 10;
structOld(N).b = 11;
structOld(N).usefulA = 506;
structOld(N).usefulB = 'at';
structOld(N).c = 12;
structOld(N).d = 'ion';
In this case, I'd like to end up with:
structNew =
1x50 struct array with fields:
usefulA
usefulB
Keeping elements with empty usefulA/usefulB fields is fine; I can get rid of them later if needed.
Using rmfield isn't great because the number of useless fields far outnumbers the useful fields.
You can create a new struct array using existing data as follows:
structNew = struct('usefulA',{structOld.usefulA},'usefulB',{structOld.usefulB});
If you have an arbitrary set of field names that you want to preserve, you could use a loop as follows. Here, I'm first extracting the data from strcutOld into a cell array data, which contains each of the arguments the the struct call in the previous line of code. data{:} is now a comma-separated list of these arguments, the last line of code below is identical to the line above.
keepFields = {'usefulA','usefulB'};
data = cell(2,numel(keepFields));
for ii=1:numel(keepFields)
data{1,ii} = keepFields{ii};
data{2,ii} = {structOld.(keepFields{ii})};
end
structNew = struct(data{:});

Matlab name assignment

I am trying to decrease some big chucks of matlab code i had from a while ago, and was hoping to get them a bit more "clean".
The VarName2,VarName3,VarName4 ...etc are provide by measured data and i will know what they are always going to be thus i gave me the name A,B ,C , the think i want changed though is the first part of the name, so every time i run the .m file I will use the input('') option
where as fname = 'SWAN' and A, B , C are the second part of the name and they are constant.
fname = input ('enter name')
fname_A = VarName2
fname_B = VarName3
fname_C = VarName4
and want to be getting
SWAN_A = VarName2
SWAN_B = VarName3
SWAN_C = VarName4
thank you
Following your advices I been trying the structure construction
S.name = input ('enter name of the data ".." ==')
S.A = A;
S.A(1,:)=[];
S.B = B;
S.B(1,:)=[];
S.C = C;
S.C(1,:)=[];
S.D = D;
S.D(1,:)=[];
S.E = E;
S.E(1,:)=[];
may i ask if i can also have an input thing command so i can change the name of the structure?
Precede the script with S='west' and then do
'S'.name = input ('enter name of the data ".." ==')
S.A = A;
Here is how I would probably store the information that you are handling:
S.name = input ('enter name')
S.A = VarName2
S.B = VarName3
S.C = VarName4
And if you want to do it a few times:
for t=3:-1:1
S(t).name = input ('enter name')
S(t).A = VarName2
S(t).B = VarName3
S(t).C = VarName4
end
In this way you could now find the struct named 'swan':
idx = strcmpi({S.name},'SWAN')
you can use eval
eval( sprintf('%s_A = VarName2;', fname ) );
eval( sprintf('%s_B = VarName3;', fname ) );
eval( sprintf('%s_C = VarName4;', fname ) );
Note that the use of eval is not recommended.
One alternative option may be to use struct with dynamic field names:
A.( fname ) = VarName2;
B.( fname ) = VarName3;
C.( fname ) = VarName4;
Now you have three structs (A, B and C) with A.SWAN equal to VarName2, B.SWAN equal to VarName3 etc.

Concatenating text from different text files into one

Suppose there are five text files. Contents of files are textfile1 = i saw an alligator, textfile2 = alligator was sitting near a tree, textfile3 = alligator was sleeping, textfile4 = parrot was flying, textfile5 = parrot was flying.
I used the code below to find paths of textfiles containing word alligator:
sdirectory = 'C:\Users\anurag\Desktop\Animals\Annotations\';
textfiles = dir([sdirectory '*.eng']);
num_of_files = length(textfiles);
C = cell(num_of_files, 1);
for w = 1:length(textfiles)
file = [sdirectory textfiles(w).name];
%// load string from a file
STR = importdata(file);
BL = cellfun(#lower, STR, 'uni',0);
%// extract string between tags
%// assuming you want to remove the angle brackets
B = regexprep(BL, '<.*?>','');
B(strcmp(B, '')) = [];
%// split each string by delimiters and add to C
tmp = regexp(B, '/| ', 'split');
C{w} = [tmp{:}];
end
where = [];
for j = 1:length(C)
file1 = [sdirectory textfiles(j).name];
if find(ismember(C{j},'alligator'))
where = [where num2str(j) '.eng, '];
disp(file1)
end
end
Finally the variable file1 will show the path of textfile containing word alligator one by one. Is there any way to concatenate the strings of textfiles containing the required word into a cell array.

How to programatically construct a large cell array

How could I construct automatically a dataset like the one below, assuming that the number of columns of matrix summary_whts is approx. 400???
lrwghts = dataset(...
{summary_whts(:,01),'w00'},...
{summary_whts(:,02),'w01'},...
{summary_whts(:,03),'w02'},...
{summary_whts(:,04),'w03'},...
{summary_whts(:,05),'w04'},...
{summary_whts(:,06),'w05'},...
{summary_whts(:,07),'w06'},...
{summary_whts(:,08),'w07'},...
{summary_whts(:,09),'w08'},...
{summary_whts(:,10),'w09'},...
{summary_whts(:,11),'w10'},...
{summary_whts(:,12),'w11'},...
'ObsNames',summary_mthd);
Why not use a simple loop to populate dataset?
nCols = size(summary_whts,1);
dataset = cell(nCols, 2);
for i = 1:nCols
dataset{i,1} = summary_whts(:,i);
dataset{i,2} = sprintf('w%04d', i);
end
dataset{end+1,1} = 'ObsNames';
dataset(end, 2} = summary_mthd;
At last, I found it! This is what I was looking for:
cat = [];
for i = 0:(size(X,2)),
cat = [cat;sprintf('w%03d',i)];
end
cat = cellstr(cat);
lrwghts = dataset({summary_whts,cat{:}},'ObsNames',cellstr(summary_mthd));