This is especially useful when looking for multiple lines from the same file, such as when producing a traceback for an error report. Reading the 5th line from the file is a simple one-liner. Notice that the line numbers in the linecache module start with 1, but if we split the string ourselves we start indexing the array from 0. We also need to strip the trailing newline from the value returned from the cache. If the requested line number falls out of the range of valid lines in the file, linecache returns an empty string.
Since linecache is used so heavily when producing tracebacks, one of the key features is the ability to find Python source modules in the import path by specifying the base name of the module.
The cache population code in linecache searches sys. Last updated on Jul 11, Created using Sphinx. Design based on "Leaves" by SmallPark. Available In: 1. Vivamus eget elit. The module loader will be asked for the source only when getlines is called, not immediately. To demonstrate use of linecache functionality, first we build a text file to store the famous Zen of Python list of software principles that influence design philosophy of Python.
When above code is executed, zen. We shall use this text file to read lines from it with getline function. Chandu yadav. The cache population code in linecache searches sys. This example looks for linecache. Since there is no copy in the current directory, the file from the standard library is found instead. Some of the features described here may not be available in earlier versions of Python. The File System. Vivamus eget elit. In posuere mi non risus. Mauris id quam posuere lectus sollicitudin varius.
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