Quand dois-je utiliser des espaces réservés \'{}\' avec .format() au lieu de \'%s\' pour le formatage de chaîne en Python ?

String Formatting in Python: Understanding '%s' Placeholders

When attempting to substitute placeholders like {0} using % formatting, you may encounter the error "TypeError: not all arguments converted during string formatting." This error often occurs due to mismatches between old-style and new-style string formatting methods.

Old-style % formatting uses % codes for formatting, where each value is specified as follows:

<code class="python">'It will cost $%d dollars.' % 95</code>

Multiple values require a tuple:

<code class="python">&quot;'%s' is longer than '%s'&quot; % (name1, name2)</code>

New-style {} formatting, on the other hand, utilizes {} codes and the .format method:

<code class="python">'It will cost ${0} dollars.'.format(95)</code>

<code class="python">&quot;'{0}' is longer than '{1}'&quot;.format(name1, name2)</code>

To fix the error in the provided code, you should use {} placeholders and call the .format method:

<code class="python">print("'{0}' is longer than '{1}'".format(name1, name2))</code>

By following these guidelines, you can ensure proper string formatting and avoid the "TypeError: not all arguments converted during string formatting" error.

Ce qui précède est le contenu détaillé de. pour plus d'informations, suivez d'autres articles connexes sur le site Web de PHP en chinois!