{"id":367,"date":"2024-11-09T18:47:42","date_gmt":"2024-11-09T18:47:42","guid":{"rendered":"https:\/\/equipomedios.com\/blog\/?p=367"},"modified":"2024-10-18T18:49:55","modified_gmt":"2024-10-18T18:49:55","slug":"iteradores-python","status":"publish","type":"post","link":"https:\/\/equipomedios.com\/blog\/iteradores-python\/","title":{"rendered":"Iteradores | Python"},"content":{"rendered":"

Iteradores<\/h1>\n

Para entender los la filosof\u00eda de los\u00a0Iteradores<\/em>, busca la\u00a0simplicidad<\/em>\u00a0de las operaciones, evitando la duplicaci\u00f3n del esfuerzo, el cual es un derroche y busca reemplazar varios de los enfoques propios con una caracter\u00edstica est\u00e1ndar, normalmente, deriva en hacer las cosas m\u00e1s legibles adem\u00e1s de m\u00e1s interoperable.<\/p>\n

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Guido van Rossum<\/em>\u00a0\u2014\u00a0A\u00f1adiendo tipado est\u00e1tico opcional a Python<\/cite>\u00a0(Adding Optional Static Typing to Python).<\/div>\n<\/blockquote>\n

Un iterador es un objeto adherido al\u00a0iterator protocol, b\u00e1sicamente esto significa que tiene una funci\u00f3n\u00a0next()<\/span>, es decir, cuando se le llama, devuelve la siguiente elemento en la secuencia, cuando no queda nada para ser devuelto, lanza la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n. Pero si se llama de forma expl\u00edcita puede ver que, una vez que el iterador est\u00e9\u00a0agotado<\/em>, al llamarlo nuevamente ver\u00e1 que se lanza la excepci\u00f3n comentada anteriormente.<\/p>\n

A continuaci\u00f3n el uso de iteradores usando del m\u00e9todo especial\u00a0__iter__()<\/span><\/code>\u00a0incluido en el\u00a0objeto integrado<\/em>\u00a0file<\/span>:<\/p>\n

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>>> <\/span>archivo<\/span> =<\/span> open<\/span>(<\/span>'\/etc\/hostname'<\/span>)<\/span>\r\n>>> <\/span>archivo<\/span>\r\n<open file '\/etc\/hostname', mode 'r' at 0x7fa44ba379c0><\/span>\r\n>>> <\/span>archivo<\/span>.<\/span>__iter__<\/span>()<\/span>\r\n<open file '\/etc\/hostname', mode 'r' at 0x7fa44ba379c0><\/span>\r\n>>> <\/span>iter<\/span>(<\/span>archivo<\/span>)<\/span>\r\n<open file '\/etc\/hostname', mode 'r' at 0x7fa44ba379c0><\/span>\r\n>>> <\/span>archivo<\/span> is<\/span> archivo<\/span>.<\/span>__iter__<\/span>()<\/span>\r\nTrue<\/span>\r\n>>> <\/span>linea<\/span> =<\/span> archivo<\/span>.<\/span>__iter__<\/span>()<\/span>\r\n>>> <\/span>linea<\/span>.<\/span>next<\/span>()<\/span>\r\n'laptop\\n'<\/span>\r\n>>> <\/span>linea<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo, el m\u00e9todo especial\u00a0__iter__()<\/span><\/code>, hace lo mismo que la funci\u00f3n integrada\u00a0iter(archivo)<\/span>.<\/p>\n
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Iteradores y secuencias<\/h2>\n
Los\u00a0iteradores<\/em>\u00a0se usan con los tipos de secuencias est\u00e1ndar. A continuaci\u00f3n, se describen algunos ejemplos:<\/p>\n
Iterar sobre la secuencia inmutable cadena de car\u00e1cter<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con la secuencia\u00a0inmutable<\/em>\u00a0de tipo\u00a0cadena de caracteres<\/span>\u00a0ASCII<\/span><\/code>:<\/p>\n
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>>> <\/span>frase<\/span> =<\/span> 'Hola Mundo'<\/span>\r\n>>> <\/span>letra<\/span> =<\/span> iter<\/span>(<\/span>frase<\/span>)<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n'H'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n'o'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n'l'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n'a'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n' '<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n'M'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n'u'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n'n'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n'd'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\n'o'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0frase<\/span><\/code>, al llegar al final mediante el iterador\u00a0letra<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n
Iterar sobre la secuencia inmutable cadena Unicode<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con la secuencia\u00a0inmutable<\/em>\u00a0de tipo\u00a0cadena de caracteres<\/span>\u00a0Unicode<\/span><\/code>:<\/p>\n
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>>> <\/span>frase<\/span> =<\/span> u<\/span>'Jekechit\u00fc'<\/span>\r\n>>> <\/span>letra<\/span> =<\/span> iter<\/span>(<\/span>frase<\/span>)<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nu'J'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nu'e'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nu'k'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nu'e'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nu'c'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nu'h'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nu'i'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nu't'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nu'\\xfc'<\/span>\r\n>>> <\/span>letra<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0frase<\/span><\/code>, al llegar al final mediante el iterador\u00a0letra<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n
Iterar sobre la secuencia inmutable tupla<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con la secuencia\u00a0inmutable<\/em>\u00a0de tipo\u00a0tupla<\/span>:<\/p>\n
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>>> <\/span>valores<\/span> =<\/span> (<\/span>\"Python\"<\/span>,<\/span> True<\/span>,<\/span> \"Zope\"<\/span>,<\/span> 5<\/span>)<\/span>\r\n>>> <\/span>valores<\/span>\r\n('Python', True, \"Zope\", 5)<\/span>\r\n>>> <\/span>valores<\/span>.<\/span>__iter__<\/span>()<\/span>\r\n<tupleiterator object at 0x7fa44b9fa450><\/span>\r\n>>> <\/span>valor<\/span> =<\/span> valores<\/span>.<\/span>__iter__<\/span>()<\/span>\r\n>>> <\/span>valor<\/span>.<\/span>next<\/span>()<\/span>\r\n'Python'<\/span>\r\n>>> <\/span>valor<\/span>.<\/span>next<\/span>()<\/span>\r\nTrue<\/span>\r\n>>> <\/span>valor<\/span>.<\/span>next<\/span>()<\/span>\r\n'Zope'<\/span>\r\n>>> <\/span>valor<\/span>.<\/span>next<\/span>()<\/span>\r\n5<\/span>\r\n>>> <\/span>valor<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0valores<\/span><\/code>, al llegar al final mediante el iterador\u00a0valor<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n
Iterar sobre la funci\u00f3n inmutable xrange<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con la secuencia\u00a0inmutable<\/em>\u00a0con la funci\u00f3n integrada\u00a0xrange()<\/span>:<\/p>\n
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>>> <\/span>lista<\/span> =<\/span> iter<\/span>(<\/span>xrange<\/span>(<\/span>5<\/span>))<\/span>\r\n>>> <\/span>lista<\/span>\r\n<rangeiterator object at 0x7fa44b9fb7b0><\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n0<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n1<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n2<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n3<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n4<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0lista<\/span><\/code>, al llegar al final se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n
Iterar sobre la secuencia mutable lista<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con la secuencia\u00a0mutable<\/em>\u00a0de tipo\u00a0lista<\/span>:<\/p>\n
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>>> <\/span>versiones_plone<\/span> =<\/span> [<\/span>2.1<\/span>,<\/span> 2.5<\/span>,<\/span> 3.6<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>,<\/span> 6<\/span>]<\/span>\r\n>>> <\/span>iter<\/span>(<\/span>versiones_plone<\/span>)<\/span>\r\n<listiterator object at 0x7fa44b9fa450><\/span>\r\n>>> <\/span>version<\/span> =<\/span> iter<\/span>(<\/span>versiones_plone<\/span>)<\/span>\r\n>>> <\/span>version<\/span>\r\n<listiterator object at 0x7fa44b9fa550><\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.1<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.5<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n3.6<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n4<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n5<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n6<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0versiones_plone<\/span><\/code>, al llegar al final mediante el iterador\u00a0version<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n
Usted puede devolver un objeto iterador en orden inverso sobre una secuencia\u00a0mutable<\/em>\u00a0de tipo\u00a0lista<\/span>\u00a0usando su funci\u00f3n integrada\u00a0__reversed__()<\/span><\/code>.<\/p>\n
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>>> <\/span>versiones_plone<\/span> =<\/span> [<\/span>2.1<\/span>,<\/span> 2.5<\/span>,<\/span> 3.6<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>,<\/span> 6<\/span>]<\/span>\r\n>>> <\/span>versiones_plone<\/span>.<\/span>__reversed__<\/span>()<\/span>\r\n<listreverseiterator object at 0xb712ebec><\/span>\r\n>>> <\/span>version<\/span> =<\/span> versiones_plone<\/span>.<\/span>__reversed__<\/span>()<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n6<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n5<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n4<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n3.6<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.5<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.1<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0versiones_plone<\/span><\/code>, al llegar al final mediante el iterador\u00a0version<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n
Tambi\u00e9n puede acceder al uso del m\u00e9todo especial\u00a0__iter__()<\/span><\/code>\u00a0incluido en la secuencia\u00a0mutable<\/em>\u00a0del tipo integrado\u00a0lista<\/span>:<\/p>\n
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>>> <\/span>versiones_plone<\/span> =<\/span> [<\/span>2.1<\/span>,<\/span> 2.5<\/span>,<\/span> 3.6<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>,<\/span> 6<\/span>]<\/span>\r\n>>> <\/span>versiones_plone<\/span>.<\/span>__iter__<\/span>()<\/span>\r\n<listiterator object at 0x7fa44b9fa510><\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
Iterar sobre la funci\u00f3n mutable range<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con la secuencia\u00a0mutable<\/em>\u00a0de la funci\u00f3n integrada\u00a0range()<\/span>:<\/p>\n
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>>> <\/span>lista<\/span> =<\/span> iter<\/span>(<\/span>range<\/span>(<\/span>5<\/span>))<\/span>\r\n>>> <\/span>lista<\/span>\r\n<listiterator object at 0x7fa44b9fa490><\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n0<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n1<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n2<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n3<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\n4<\/span>\r\n>>> <\/span>lista<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0lista<\/span><\/code>, al llegar al final se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n<\/div>\n
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Iteradores y conjuntos<\/h2>\n
Los\u00a0iteradores<\/em>\u00a0se usan con los tipos de conjuntos est\u00e1ndar. A continuaci\u00f3n, se describen algunos ejemplos:<\/p>\n
Iterar sobre el conjunto mutable<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con el conjunto\u00a0mutable<\/em>\u00a0de tipo\u00a0conjuntos<\/span>:<\/p>\n
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>>> <\/span>versiones_plone<\/span> =<\/span> set<\/span>([<\/span>2.1<\/span>,<\/span> 2.5<\/span>,<\/span> 3.6<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>,<\/span> 6<\/span>,<\/span> 4<\/span>])<\/span>\r\n>>> <\/span>version<\/span> =<\/span> iter<\/span>(<\/span>versiones_plone<\/span>)<\/span>\r\n>>> <\/span>version<\/span>\r\n<setiterator object at 0x7fac9c7c7a50><\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.5<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n4<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n5<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n6<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.1<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n3.6<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0versiones_plone<\/span><\/code>, al llegar al final mediante el iterador\u00a0version<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n
Iterar sobre el conjunto inmutable<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con el conjunto\u00a0inmutable<\/em>\u00a0de tipo\u00a0conjuntos<\/span>:<\/p>\n
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>>> <\/span>versiones_plone<\/span> =<\/span> frozenset<\/span>([<\/span>6<\/span>,<\/span> 2.1<\/span>,<\/span> 2.5<\/span>,<\/span> 3.6<\/span>,<\/span> 4<\/span>,<\/span> 5<\/span>,<\/span> 4<\/span>,<\/span> 2.5<\/span>])<\/span>\r\n>>> <\/span>version<\/span> =<\/span> iter<\/span>(<\/span>versiones_plone<\/span>)<\/span>\r\n>>> <\/span>version<\/span>\r\n<setiterator object at 0x7fac9c7c7cd0><\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.5<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n4<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n5<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n6<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.1<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n3.6<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0versiones_plone<\/span><\/code>, al llegar al final mediante el iterador\u00a0version<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n<\/div>\n
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Iteradores y mapeos<\/h2>\n
Los\u00a0iteradores<\/em>\u00a0se usan con los tipos de secuencias est\u00e1ndar. A continuaci\u00f3n, se describen algunos ejemplos:<\/p>\n
Iterar sobre las claves del diccionario<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con la secuencia de\u00a0mapeo<\/em>, tipo\u00a0diccionario<\/span>, por defecto muestra la clave de la secuencia:<\/p>\n
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>>> <\/span>versiones_plone<\/span> =<\/span> dict<\/span>(<\/span>python<\/span>=<\/span>2.7<\/span>,<\/span> zope<\/span>=<\/span>2.13<\/span>,<\/span> plone<\/span>=<\/span>5.1<\/span>)<\/span>\r\n>>> <\/span>paquete<\/span> =<\/span> iter<\/span>(<\/span>versiones_plone<\/span>)<\/span>\r\n>>> <\/span>paquete<\/span>\r\n<dictionary-keyiterator object at 0x7fa44b9e99f0><\/span>\r\n>>> <\/span>paquete<\/span>.<\/span>next<\/span>()<\/span>\r\n'zope'<\/span>\r\n>>> <\/span>paquete<\/span>.<\/span>next<\/span>()<\/span>\r\n'python'<\/span>\r\n>>> <\/span>paquete<\/span>.<\/span>next<\/span>()<\/span>\r\n'plone'<\/span>\r\n>>> <\/span>paquete<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0versiones_plone<\/span><\/code>, al llegar al final mediante el iterador\u00a0paquete<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n
Iterar sobre los valores del diccionario<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con la secuencia de\u00a0mapeo<\/em>, tipo\u00a0diccionario<\/span>\u00a0para mostrar el valor de una clave usando el m\u00e9todo integrado\u00a0itervalues()<\/span>:<\/p>\n
\n
\n
>>> <\/span>versiones_plone<\/span> =<\/span> dict<\/span>(<\/span>python<\/span>=<\/span>2.7<\/span>,<\/span> zope<\/span>=<\/span>2.13<\/span>,<\/span> plone<\/span>=<\/span>5.1<\/span>)<\/span>\r\n>>> <\/span>version<\/span> =<\/span> iter<\/span>(<\/span>versiones_plone<\/span>.<\/span>itervalues<\/span>())<\/span>\r\n>>> <\/span>version<\/span>\r\n<dictionary-valueiterator object at 0x7fa44b9e9c00><\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.13<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n2.7<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\n5.1<\/span>\r\n>>> <\/span>version<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0versiones_plone<\/span><\/code>, al llegar al final mediante el iterador\u00a0version<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n
Iterar sobre los elementos del diccionario<\/strong><\/p>\n
A continuaci\u00f3n, un ejemplo del uso de los iteradores con la secuencia de\u00a0mapeo<\/em>, tipo\u00a0diccionario<\/span>\u00a0para mostrar el par clave\/valor usando el m\u00e9todo integrado\u00a0iteritems()<\/span>:<\/p>\n
\n
\n
>>> <\/span>versiones_plone<\/span> =<\/span> dict<\/span>(<\/span>python<\/span>=<\/span>2.7<\/span>,<\/span> zope<\/span>=<\/span>2.13<\/span>,<\/span> plone<\/span>=<\/span>5.1<\/span>)<\/span>\r\n>>> <\/span>paquete<\/span> =<\/span> iter<\/span>(<\/span>versiones_plone<\/span>.<\/span>iteritems<\/span>())<\/span>\r\n>>> <\/span>paquete<\/span>\r\n<dictionary-itemiterator object at 0x7fa44b9e9b50><\/span>\r\n>>> <\/span>paquete<\/span>.<\/span>next<\/span>()<\/span>\r\n('zope', 2.13)<\/span>\r\n>>> <\/span>paquete<\/span>.<\/span>next<\/span>()<\/span>\r\n('python', 2.7)<\/span>\r\n>>> <\/span>paquete<\/span>.<\/span>next<\/span>()<\/span>\r\n('plone', 5.1)<\/span>\r\n>>> <\/span>paquete<\/span>.<\/span>next<\/span>()<\/span>\r\nTraceback (most recent call last):<\/span>\r\n  File \"<stdin>\"<\/span>, line 1<\/span>, in <module><\/span>\r\nStopIteration<\/span>\r\n<\/pre>\n<\/div>\n<\/div>\n
En el ejemplo anterior, cuando se itera en la secuencia\u00a0versiones_plone<\/span><\/code>, al llegar al final mediante el iterador\u00a0paquete<\/span><\/code>\u00a0se llama a la excepci\u00f3n\u00a0StopIteration<\/span>\u00a0y se causa el detener la iteraci\u00f3n.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
Iteradores Para entender los la filosof\u00eda de los\u00a0Iteradores, busca la\u00a0simplicidad\u00a0de las operaciones, evitando la duplicaci\u00f3n del esfuerzo, el cual es un derroche y busca reemplazar varios de los enfoques propios con una caracter\u00edstica est\u00e1ndar, normalmente, deriva en hacer las cosas m\u00e1s legibles adem\u00e1s de m\u00e1s interoperable. Guido van Rossum\u00a0\u2014\u00a0A\u00f1adiendo tipado est\u00e1tico opcional a Python\u00a0(Adding Optional […]<\/p>\n","protected":false},"author":1,"featured_media":331,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[39,40],"tags":[],"class_list":["post-367","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-programacion","category-python"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/equipomedios.com\/blog\/wp-content\/uploads\/2024\/08\/python-logo-master-v3-TM.png?fit=601%2C203&ssl=1","jetpack_sharing_enabled":true,"jetpack-related-posts":[],"jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/posts\/367","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/comments?post=367"}],"version-history":[{"count":1,"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/posts\/367\/revisions"}],"predecessor-version":[{"id":368,"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/posts\/367\/revisions\/368"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/media\/331"}],"wp:attachment":[{"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/media?parent=367"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/categories?post=367"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/equipomedios.com\/blog\/wp-json\/wp\/v2\/tags?post=367"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}