Copying a list<\/strong> means creating a new list with the same items<\/strong>.<\/p>\n This is useful when:<\/p>\n You want to change one list<\/p>\n<\/li>\n But keep the original list safe<\/p>\n<\/li>\n<\/ul>\n If you don\u2019t copy properly, both lists may change together \ud83d\ude1f<\/p>\n Output:<\/p>\n \ud83d\udc49 Both changed because they point to the same list<\/strong>.<\/p>\n This is the simplest and best<\/strong> way.<\/p>\n All above methods create a shallow copy<\/strong>.<\/p>\n This is enough for simple lists<\/strong>.<\/p>\n \u274c This does NOT create a copy.<\/p>\n \u2714 Use This chapter is ideal for:<\/p>\n Python beginner books<\/p>\n<\/li>\n School & college students<\/p>\n<\/li>\n Self-learners<\/p>\n<\/li>\n<\/ul>\n If you want next, I can write:<\/p>\n Join Lists<\/strong><\/p>\n<\/li>\n Tuple Basics<\/strong><\/p>\n<\/li>\n Set Basics<\/strong><\/p>\n<\/li>\n Dictionary Basics<\/strong><\/p>\n<\/li>\n List Exercises<\/strong><\/p>\n<\/li>\n<\/ul>\n Just tell me \ud83d\ude0a<\/p>\n","protected":false},"excerpt":{"rendered":" 1. What Does \u201cCopy List\u201d Mean? Copying a list means creating a new list with the same items. This is useful when: You want to change one list But keep the original list safe...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21],"tags":[],"class_list":["post-2444","post","type-post","status-publish","format-standard","hentry","category-python"],"_links":{"self":[{"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/posts\/2444","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/comments?post=2444"}],"version-history":[{"count":2,"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/posts\/2444\/revisions"}],"predecessor-version":[{"id":2446,"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/posts\/2444\/revisions\/2446"}],"wp:attachment":[{"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/media?parent=2444"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/categories?post=2444"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/demo.materiamedica.net\/demo6\/wp-json\/wp\/v2\/tags?post=2444"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}\n
2. Why Copying Lists is Important<\/h2>\n
Example (Problem)<\/h3>\n
list1 = [1<\/span>, 2<\/span>, 3<\/span>]
\nlist2 = list1<\/code><\/code>list2.append(4<\/span>)<\/p>\n<\/code><\/code>print<\/span>(list1)
\nprint<\/span>(list2)<\/p>\n<\/div>\n<\/div>\n[1, 2, 3, 4]
\n[1, 2, 3, 4]
\n<\/code><\/div>\n<\/div>\n3. Correct Way to Copy a List<\/h2>\n
Method 1: Using
copy()<\/code><\/h2>\nExample<\/h3>\n
list1 = [1<\/span>, 2<\/span>, 3<\/span>]
\nlist2 = list1.copy()<\/code><\/code>list2.append(4<\/span>)<\/p>\n<\/code><\/code>print<\/span>(list1)
\nprint<\/span>(list2)<\/p>\n<\/div>\n<\/div>\n4. Method 2: Using
list()<\/code> Function<\/h2>\nExample<\/h3>\n
list1 = [\"apple\"<\/span>, \"banana\"<\/span>]
\nlist2 = list<\/span>(list1)<\/code><\/code>print<\/span>(list2)<\/p>\n<\/div>\n<\/div>\n5. Method 3: Using Slice (
[:]<\/code>)<\/h2>\nExample<\/h3>\n
list1 = [10<\/span>, 20<\/span>, 30<\/span>]
\nlist2 = list1[:]<\/code><\/code>print<\/span>(list2)<\/p>\n<\/div>\n<\/div>\n6. Copy List Using Loop<\/h2>\n
Example<\/h3>\n
list1 = [1<\/span>, 2<\/span>, 3<\/span>]
\nlist2 = []<\/code><\/code>for<\/span> item in<\/span> list1:
\nlist2.append(item)<\/p>\n<\/code><\/code>print<\/span>(list2)<\/p>\n<\/div>\n<\/div>\n7. Shallow Copy (Simple Note)<\/h2>\n
8. Common Beginner Mistakes<\/h2>\n
\u274c Using
=<\/code> Instead of Copy<\/h3>\nlist2 = list1
\n<\/code><\/div>\n<\/div>\n\u2714 Correct<\/h3>\n
list2 = list1.copy()
\n<\/code><\/div>\n<\/div>\n9. Simple Practice Examples<\/h2>\n
Example 1: Copy and Change<\/h3>\n
colors = [\"red\"<\/span>, \"blue\"<\/span>]
\nnew_colors = colors.copy()<\/code><\/code>new_colors.append(“green”<\/span>)
\nprint<\/span>(colors)
\nprint<\/span>(new_colors)<\/p>\n<\/div>\n<\/div>\nExample 2: Copy Numbers<\/h3>\n
nums = [5<\/span>, 10<\/span>, 15<\/span>]
\nnums2 = nums[:]<\/code><\/code>print<\/span>(nums2)<\/p>\n<\/div>\n<\/div>\nExample 3: Safe Backup<\/h3>\n
original = [1<\/span>, 2<\/span>, 3<\/span>]
\nbackup = list<\/span>(original)<\/code><\/code>print<\/span>(backup)<\/p>\n<\/div>\n<\/div>\n10. Summary (Copy Lists)<\/h2>\n
copy()<\/code> to copy list
\u2714 list()<\/code> and slicing also work
\u2714 Never use =<\/code> to copy
\u2714 Copy keeps original list safe<\/p>\n\ud83d\udcd8 Perfect for Beginner eBook<\/h3>\n
\n
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