从字符串格式化日期 [英] Format a date from a string

问题描述

我正在尝试将日期从字符串格式化为另一种格式.

I'm trying to format a date from a string into another format.

例如:将2012-05-29 23:55:52转换为29/05 *newline* 2010.

我认为我只是不了解NSDate和NSDateFormatter的逻辑.

I just don't get the logics behind NSDate and NSDateFormatter, I think..

任何帮助将不胜感激.谢谢:)

Any help will be appreciated. Thanks :)

推荐答案

您将需要创建NSDateFormatter，然后将其dateFormat设置为与您拥有的第一个日期匹配，例如:

You will need to create an NSDateFormatter, and then set it's dateFormat to match the first date you have, eg:

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

这将设置您的日期格式器以识别您的日期字符串.然后，您可以使用

That will set your date formatter to recognise your date string. You can then obtain an NSDate object from this using

NSDate *myDate = [dateFormatter dateFromString:myDateString]; // myDateString is the 2012-05-29 23:55:52 string

这为您提供了代表该日期的完整NSDate对象.现在，您需要重新格式化日期并将其重新转换为字符串，因此将格式化程序上的dateFormat设置为新格式​​，并获得返回日期的新字符串表示形式:

This gives you a full NSDate object representing that date. Now you need to reformat the date and turn it back into a string, so set the dateFormat on your formatter to the new format, and get a new string representation of the returned date:

[dateFormatter setDateFormat:@"dd/MM\nyyyy"];
NSString *newlyFormattedDateString = [dateFormatter stringFromDate:myDate];
[dateFormatter release], dateFormatter = nil;

瞧！您有新日期:)

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