大约有 40,000 项符合查询结果(耗时:0.0386秒) [XML]

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What's the difference between eval, exec, and compile?

...gt; g = dict() >>> l = dict() >>> exec('global a; a, b = 123, 42', g, l) >>> g['a'] 123 >>> l {'b': 42} (If you display the value of the entire g, it would be much longer, because exec and eval add the built-ins module as __builtins__ to the globals automaticall...
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How do I check if a C++ std::string starts with a certain string, and convert a substring to an int?

...only match at that position or earlier. For example: std::string test = "0123123"; size_t match1 = test.rfind("123"); // returns 4 (rightmost match) size_t match2 = test.rfind("123", 2); // returns 1 (skipped over later match) size_t match3 = test.rfind("123", 0); // returns std::string::npos (i...
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How to pass an array within a query string?

...a comma separated list of items: let data = { str: 'abc', arr: ['abc', 123] } new URLSearchParams(data).toString(); // ?str=abc&arr=abc,123 share | improve this answer | ...
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Java: How to set Precision for double value? [duplicate]

...ts. If you only want to print, use it this way: System.out.printf("%.2f",123.234); share | improve this answer | follow | ...
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Git - working on wrong branch - how to copy changes to existing topic branch

... Sounds like all you need is the following: git stash git checkout branch123 git stash apply Then you should be back on your own branch without touching the master branch. share | improve this a...
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Fastest check if row exists in PostgreSQL

... How about simply: select 1 from tbl where userid = 123 limit 1; where 123 is the userid of the batch that you're about to insert. The above query will return either an empty set or a single row, depending on whether there are records with the given userid. If this turns o...
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Summarizing multiple columns with dplyr? [duplicate]

...brary(dplyr) library(purrrlyr) library(data.table) library(bench) set.seed(123) n <- 10000 df <- data.frame( a = sample(1:5, n, replace = TRUE), b = sample(1:5, n, replace = TRUE), c = sample(1:5, n, replace = TRUE), d = sample(1:5, n, replace = TRUE), grp = sample(1:3, n, replac...
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How to Implement Custom Table View Section Headers and Footers with Storyboard

...bel to the header cell set the tag of the label to a specific number (e.g. 123) In your tableView:viewForHeaderInSection: method get the label by calling: UILabel *label = (UILabel *)[headerView viewWithTag:123]; Now you can use the label to set a new title: [label setText:@"New Titl...
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How to overcome TypeError: unhashable type: 'list'

... else: d[key] = [value] print d # {'AAA': ['111', '112'], 'AAC': ['123'], 'AAB': ['111']} Note that if you are using Python 3.x, you'll have to make a minor adjustment to get it work properly. If you open the file with rb, you'll need to use line = line.split(b'x') (which makes sure you ar...
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How to print formatted BigDecimal values?

...nts money, and I need to print its value in the browser in a format like $123.00 , $15.50 , $0.33 . 6 Answers ...