if (File.Exists("file.exe"))
{	//file exist
} else { //does not exist
}

>>> import os
>>> os.path.isfile("d:\\Package1\\package1\\fibo.py")
True
>>> os.path.isfile("d:/Package1/package1/fibo.py")
True
>>> os.path.isfile("d:\\nonexisting.txt")

[ -f /etc/resolv.conf ] && { echo "$FILE exist."; cp "$FILE" /tmp/; }

from pathlib import Path
if Path('filename.txt').is_file(): print ("File exist")
else: print ("File not exist")

# check if file exists
from os.path import exists
file_exists = exists("/content/sample_data/california_housing_test.csv")
print(file_exists)
#True
from pathlib import Path
path = Path("/content/sample_data/california_housing_test.csv")
path.is_file()
#False

#define BOOST_FILESYSTEM_VERSION 3
#define BOOST_FILESYSTEM_NO_DEPRECATED
#include <boost/filesystem.hpp>
namespace fs = boost::filesystem;
/** * \brief Return the filenames of all files that have the specified extension * in the specified directory and all subdirectories. */
std::vector<fs::path> get_all(fs::path const & root, std::string const & ext)
{ std::vector<fs::path> paths; if (fs::exists(root) && fs::is_directory(root)) { for (auto const & entry : fs::recursive_directory_iterator(root)) { if (fs::is_regular_file(entry) && entry.path().extension() == ext) paths.emplace_back(entry.path().filename()); } } return paths;
}