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Merged
merged 5 commits into from
Nov 13, 2025
+66 −29
Merged

Provide suitable string format for TGraph constustructors #20390

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65c0817
No need to const_cast TH1 in TGraph constructor
linev Nov 12, 2025
2df7c35
Guess TGraph text format from extension
linev Nov 12, 2025
b2d1d4e
Guess TGraphErrors text format when not specified
linev Nov 12, 2025
a4a3e2b
Guess TGraphAsymmErrors text format when not specified
linev Nov 12, 2025
e86c3d3
No need to specify format in TGraph::SaveAs tests
linev Nov 12, 2025
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25 changes: 18 additions & 7 deletions hist/hist/src/TGraph.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -358,12 +358,13 @@ TGraph::TGraph(const TH1 *h)
Error("TGraph", "Histogram must be 1-D; h %s is %d-D", h->GetName(), h->GetDimension());
fNpoints = 0;
} else {
fNpoints = ((TH1*)h)->GetXaxis()->GetNbins();
fNpoints = h->GetXaxis()->GetNbins();
}

if (!CtorAllocate()) return;
if (!CtorAllocate())
return;

TAxis *xaxis = ((TH1*)h)->GetXaxis();
auto xaxis = h->GetXaxis();
for (Int_t i = 0; i < fNpoints; i++) {
fX[i] = xaxis->GetBinCenter(i + 1);
fY[i] = h->GetBinContent(i + 1);
Expand Down Expand Up @@ -440,6 +441,7 @@ TGraph::TGraph(const TF1 *f, Option_t *option)
/// The string format is by default `"%lg %lg"`.
/// This is a standard c formatting for `scanf()`.
/// For example, set format to `"%lg,%lg"` for a comma-separated file.
/// If format string is empty, suitable value will be provided based on file extension
///
/// If columns of numbers should be skipped, a `"%*lg"` or `"%*s"` for each column
/// can be added, e.g. `"%lg %*lg %lg"` would read x-values from the first and
Expand Down Expand Up @@ -473,11 +475,21 @@ TGraph::TGraph(const char *filename, const char *format, Option_t *option)
std::string line;
Int_t np = 0;

// No delimiters specified (standard constructor).
if (strcmp(option, "") == 0) {
TString format_ = format;

if (!option || !*option) { // No delimiters specified (standard constructor).
// is empty format string specified - try to guess format from the file extension
if (format_.IsNull()) {
if (fname.EndsWith(".txt", TString::kIgnoreCase))
format_ = "%lg %lg";
else if (fname.EndsWith(".tsv", TString::kIgnoreCase))
format_ = "%lg\t%lg";
else
format_ = "%lg,%lg";
}

while (std::getline(infile, line, '\n')) {
if (2 != sscanf(line.c_str(), format, &x, &y)) {
if (2 != sscanf(line.c_str(), format_.Data(), &x, &y)) {
continue; //skip empty and ill-formed lines
}
SetPoint(np, x, y);
Expand All @@ -489,7 +501,6 @@ TGraph::TGraph(const char *filename, const char *format, Option_t *option)
} else {

// Checking format and creating its boolean counterpart
TString format_ = TString(format) ;
format_.ReplaceAll(" ", "") ;
format_.ReplaceAll("\t", "") ;
format_.ReplaceAll("lg", "") ;
Expand Down
25 changes: 19 additions & 6 deletions hist/hist/src/TGraphAsymmErrors.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -289,6 +289,8 @@ TGraphAsymmErrors::TGraphAsymmErrors(const TH1* pass, const TH1* total, Option_t
/// - format = `"%lg %lg %lg %lg"` read only 4 first columns into X, Y, EYL, EYH
/// - format = `"%lg %lg %lg %lg %lg %lg"` read only 6 first columns into X, Y, EXL, EXH, EYL, EYH
///
/// If format string is empty, suitable value will be provided based on file extension
///
/// For files separated by a specific delimiter different from ' ' and `\\t` (e.g. `;` in csv files)
/// you can avoid using `%*s` to bypass this delimiter by explicitly specify the `option` argument,
/// e.g. `option=" \\t,;"` for columns of figures separated by any of these characters (`' ', '\\t', ',', ';'`)
Expand All @@ -314,18 +316,30 @@ TGraphAsymmErrors::TGraphAsymmErrors(const char *filename, const char *format, O
std::string line;
Int_t np = 0;

if (strcmp(option, "") == 0) { // No delimiters specified (standard constructor).
TString format_ = format;

if (!option || !*option) { // No delimiters specified (standard constructor).

Int_t ncol = 6;
if (format_.IsNull()) {
if (fname.EndsWith(".txt", TString::kIgnoreCase))
format_ = "%lg %lg %lg %lg %lg %lg";
else if (fname.EndsWith(".tsv", TString::kIgnoreCase))
format_ = "%lg\t%lg\t%lg\t%lg\t%lg\t%lg";
else
format_ = "%lg,%lg,%lg,%lg,%lg,%lg";
} else
ncol = TGraphErrors::CalculateScanfFields(format); //count number of columns in format

Int_t ncol = TGraphErrors::CalculateScanfFields(format); //count number of columns in format
Int_t res;
while (std::getline(infile, line, '\n')) {
exl = exh = eyl = eyh = 0.;
if (ncol < 3) {
res = sscanf(line.c_str(), format, &x, &y);
res = sscanf(line.c_str(), format_.Data(), &x, &y);
} else if (ncol < 5) {
res = sscanf(line.c_str(), format, &x, &y, &eyl, &eyh);
res = sscanf(line.c_str(), format_.Data(), &x, &y, &eyl, &eyh);
} else {
res = sscanf(line.c_str(), format, &x, &y, &exl, &exh, &eyl, &eyh);
res = sscanf(line.c_str(), format_.Data(), &x, &y, &exl, &exh, &eyl, &eyh);
}
if (res < 2) {
continue; //skip empty and ill-formed lines
Expand All @@ -339,7 +353,6 @@ TGraphAsymmErrors::TGraphAsymmErrors(const char *filename, const char *format, O
} else { // A delimiter has been specified in "option"

// Checking format and creating its boolean equivalent
TString format_ = TString(format) ;
format_.ReplaceAll(" ", "") ;
format_.ReplaceAll("\t", "") ;
format_.ReplaceAll("lg", "") ;
Expand Down
25 changes: 19 additions & 6 deletions hist/hist/src/TGraphErrors.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -223,6 +223,8 @@ TGraphErrors::TGraphErrors(const TH1 *h)
/// - format = `"%lg %lg %lg"` read only 3 first columns into X,Y and EY
/// - format = `"%lg %lg %lg %lg"` read only 4 first columns into X,Y,EX,EY.
///
/// If format string is empty, suitable value will be provided based on file extension
///
/// For files separated by a specific delimiter different from ' ' and `\\t` (e.g. `;` in csv files)
/// you can avoid using `%*s` to bypass this delimiter by explicitly specify the `option` argument,
/// e.g. `option=" \\t,;"` for columns of figures separated by any of these characters (`' ', '\\t', ',', ';'`)
Expand All @@ -248,18 +250,30 @@ TGraphErrors::TGraphErrors(const char *filename, const char *format, Option_t *o
std::string line;
Int_t np = 0;

if (strcmp(option, "") == 0) { // No delimiters specified (standard constructor).
TString format_ = format;

if (!option || !*option) { // No delimiters specified (standard constructor).

Int_t ncol = 4;
if (format_.IsNull()) {
if (fname.EndsWith(".txt", TString::kIgnoreCase))
format_ = "%lg %lg %lg %lg";
else if (fname.EndsWith(".tsv", TString::kIgnoreCase))
format_ = "%lg\t%lg\t%lg\t%lg";
else
format_ = "%lg,%lg,%lg,%lg";
} else
ncol = CalculateScanfFields(format); //count number of columns in format

Int_t ncol = CalculateScanfFields(format); //count number of columns in format
Int_t res;
while (std::getline(infile, line, '\n')) {
ex = ey = 0;
if (ncol < 3) {
res = sscanf(line.c_str(), format, &x, &y);
res = sscanf(line.c_str(), format_.Data(), &x, &y);
} else if (ncol < 4) {
res = sscanf(line.c_str(), format, &x, &y, &ey);
res = sscanf(line.c_str(), format_.Data(), &x, &y, &ey);
} else {
res = sscanf(line.c_str(), format, &x, &y, &ex, &ey);
res = sscanf(line.c_str(), format_.Data(), &x, &y, &ex, &ey);
}
if (res < 2) {
continue; //skip empty and ill-formed lines
Expand All @@ -273,7 +287,6 @@ TGraphErrors::TGraphErrors(const char *filename, const char *format, Option_t *o
} else { // A delimiter has been specified in "option"

// Checking format and creating its boolean equivalent
TString format_ = TString(format) ;
format_.ReplaceAll(" ", "") ;
format_.ReplaceAll("\t", "") ;
format_.ReplaceAll("lg", "") ;
Expand Down
20 changes: 10 additions & 10 deletions hist/hist/test/test_TGraph_SaveAs.cxx
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ TEST(TGraphsa, SaveGraphAsCSV)

gr.SaveAs("graph.csv");

auto gr1 = new TGraph("graph.csv", "%lg,%lg");
auto gr1 = new TGraph("graph.csv", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand All @@ -42,7 +42,7 @@ TEST(TGraphsa, SaveGraphAsTSV)

gr.SaveAs("graph.tsv");

auto gr1 = new TGraph("graph.tsv", "%lg\t%lg");
auto gr1 = new TGraph("graph.tsv", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand All @@ -57,7 +57,7 @@ TEST(TGraphsa, SaveGraphAsTXT)

gr.SaveAs("graph.txt");

auto gr1 = new TGraph("graph.txt", "%lg %lg");
auto gr1 = new TGraph("graph.txt", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand All @@ -72,7 +72,7 @@ TEST(TGraphsa, SaveGraphErrorsAsCSV)

gr.SaveAs("grapherrors.csv", "asroot"); // << asroot important for order of values

auto gr1 = new TGraphErrors("grapherrors.csv", "%lg,%lg,%lg,%lg");
auto gr1 = new TGraphErrors("grapherrors.csv", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand All @@ -90,7 +90,7 @@ TEST(TGraphsa, SaveGraphErrorsAsTSV)

gr.SaveAs("grapherrors.tsv", "asroot"); // << asroot important for order of values

auto gr1 = new TGraphErrors("grapherrors.tsv", "%lg\t%lg\t%lg\t%lg");
auto gr1 = new TGraphErrors("grapherrors.tsv", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand All @@ -107,7 +107,7 @@ TEST(TGraphsa, SaveGraphErrorsAsTXT)

gr.SaveAs("grapherrors.txt", "asroot"); // << asroot important for order of values

auto gr1 = new TGraphErrors("grapherrors.txt", "%lg %lg %lg %lg");
auto gr1 = new TGraphErrors("grapherrors.txt", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand All @@ -125,7 +125,7 @@ TEST(TGraphsa, SaveGraphAsymmErrorsAsCSV)

gr.SaveAs("graphasymmrrors.csv", "asroot"); // << asroot important for order of values

auto gr1 = new TGraphAsymmErrors("graphasymmrrors.csv", "%lg,%lg,%lg,%lg,%lg,%lg");
auto gr1 = new TGraphAsymmErrors("graphasymmrrors.csv", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand All @@ -145,7 +145,7 @@ TEST(TGraphsa, SaveGraphAsymmErrorsAsTSV)

gr.SaveAs("graphasymmrrors.tsv", "asroot"); // << asroot important for order of values

auto gr1 = new TGraphAsymmErrors("graphasymmrrors.tsv", "%lg\t%lg\t%lg\t%lg\t%lg\t%lg");
auto gr1 = new TGraphAsymmErrors("graphasymmrrors.tsv", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand All @@ -164,7 +164,7 @@ TEST(TGraphsa, SaveGraphAsymmErrorsAsTXT)

gr.SaveAs("graphasymmrrors.txt", "asroot"); // << asroot important for order of values

auto gr1 = new TGraphAsymmErrors("graphasymmrrors.txt", "%lg %lg %lg %lg %lg %lg");
auto gr1 = new TGraphAsymmErrors("graphasymmrrors.txt", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand All @@ -183,7 +183,7 @@ TEST(TGraphsa, SaveGraphAsymmErrorsAsOnlyErrorsCSV)

gr.SaveAs("graphasymmrrors_reduce.csv", "asroot errors"); // << asroot important for order of values

auto gr1 = new TGraphErrors("graphasymmrrors_reduce.csv", "%lg,%lg,%lg,%lg");
auto gr1 = new TGraphErrors("graphasymmrrors_reduce.csv", "");
EXPECT_EQ(gr1->GetN(), NP);

for (int n = 0; n < NP; ++n) {
Expand Down
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