Css/xpath selector number of child nodes/parent/sibling nodes

0. Refer to 1. initialization

 from Import Selectorin [326]: text="" "...: <div> ...:     <a>1a</a> ...     : <p>2p</p> ...:     <p>3p</p> ...     : </div> "" " In [327]: sel=selector (text=text) in [print(sel.extract ())
2. Parent node/previous next sibling node
In [329]: Sel.xpath ('//a/Parent::*/p'). Extract () out[329]: ['<p>2p</p>','<p>3p</p>']in [[+]: Sel.xpath ('//p/preceding-sibling::a'). Extract () out[330]: ['<a>1a</a>']in [331]: Sel.xpath ('//a/following-sibling::p'). Extract () out[331]: ['<p>2p</p>','<p>3p</p>']
3.CSS number of sub-nodes 3.1 general
# Full child node list , counting from the first child node, and satisfying child node tag qualificationIn [332]: Sel.css ('a: Nth-child (1) '). Extract () out[332]: ['<a>1a</a>']# complete list of child nodes, counting from the last child node, and satisfying the child node tag limitIn [333]: Sel.css ('a: Nth-last-child (1) '). Extract () out[333]: []in [334]: Sel.css ('p:nth-child (1)'). Extract () out[334]: []in [335]: Sel.css ('P:nth-child (2)'). Extract () out[335]: ['<p>2p</p>']in [336]: Sel.css ('P:nth-child (3)'). Extract () out[336]: ['<p>3p</p>']in [337]: Sel.css ('p:nth-last-child (1)'). Extract () out[337]: ['<p>3p</p>']in [338]: Sel.css ('P:nth-last-child (2)'). Extract () out[338]: ['<p>2p</p>']in [339]: Sel.css ('P:nth-last-child (3)'). Extract () out[339]: []
3.2 Special Reference
In [340]: Sel.css ('a: First-child '). Extract () out[340]: ['<a>1a</a>']in [341]: Sel.css ('a: Last-child '). Extract () out[341]: []in [342]: Sel.css ('P:first-child'). Extract () out[342]: []in [343]: Sel.css ('P:last-child'). Extract () out[343]: ['<p>3p</p>']
3.3 The above-child is modified to-of-type, and only the corresponding list of sub-nodes after filtering is counted 4. Xpath Number of child nodes
In [344]: Sel.xpath ('//div'). Extract () out[344]: ['<div>\n <a>1a</a>\n <p>2p</p>\n <p>3p</p>\n</div>']in [345]: Sel.xpath ('//div/*'). Extract () out[345]: ['<a>1a</a>','<p>2p</p>','<p>3p</p>']in [346]: Sel.xpath ('//div/node ()'). Extract () out[346]: ['\ n','<a>1a</a>','\ n','<p>2p</p>','\ n','<p>3p</p>','\ n']in [347]: Sel.xpath ('//div/a'). Extract () out[347]: ['<a>1a</a>']in [348]: Sel.xpath ('//div/p'). Extract () out[348]: ['<p>2p</p>','<p>3p</p>']in [349]:in [349]: Sel.xpath ('//div/a[1]'). Extract () out[349]: ['<a>1a</a>']in [[Sel.xpath]:'//div/a[last ()]'). Extract () out[350]: ['<a>1a</a>']in [351]:in [351]: Sel.xpath ('//div/p[1] '). Extract ()#the equivalent of a filtered list of child nodesOUT[351]: ['<p>2p</p>']in [352]: Sel.xpath ('//div/p[Last ()] '). Extract () out[352]: ['<p>3p</p>']in [353]: Sel.xpath ('//div/p[Last ()-1] '). Extract () out[353]: ['<p>2p</p>']in [354]:in [354]: Sel.xpath ('//div/*[1]'). Extract ()#Full child node listOUT[354]: ['<a>1a</a>']in [355]: Sel.xpath ('//div/*[last ()]'). Extract () out[355]: ['<p>3p</p>']in [356]:in [356]: Sel.xpath ('//div/node () [1]'). Extract ()#include plain textOUT[356]: ['\ n']in [357]: Sel.xpath ('//div/node () [Last ()]'). Extract () out[357]: ['\ n']
Css/xpath selector number of child nodes/parent/sibling nodes