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Bash conditionals: how to “and” expressions? (if [ ! -z $VAR && -e $VAR ])
... -e $VAR ] , but it turns out that was also evaluating as true on an empty string; which I do not want.
5 Answers
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Jinja2 template variable if None Object set a default value
...p.User['first_name'] if p != None else 'NONE' }}
or if you need an empty string:
{{ p.User['first_name'] if p != None }}
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Java FileOutputStream Create File if not exists
Is there a way to use FileOutputStream in a way that if a file (String filename) does not exist, then it will create it?
9 ...
URL query parameters to dict python
...llib.parse.parse_qs() and urllib.parse.parse_qsl() methods parse out query strings, taking into account that keys can occur more than once and that order may matter.
If you are still on Python 2, urllib.parse was called urlparse.
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LINQ with groupby and count
...ready have a list/array of some class that looks like
class UserInfo {
string name;
int metric;
..etc..
}
...
List<UserInfo> data = ..... ;
When you do data.GroupBy(x => x.metric), it means "for each element x in the IEnumerable defined by data, calculate it's .metric, then gr...
How to set the current working directory? [duplicate]
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@Pooja25 The path must be a string. in addition, chdir expects a directory name, but you are specifying a file.
– mwil.me
Jan 14 '16 at 1:25
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How to serialize SqlAlchemy result to JSON?
...(db.Integer, primary_key=True, auto_increment=True)
email = db.Column(db.String(200), unique=True)
@app.route('/users/')
def users():
users = User.query.all()
return jsonify(users)
if __name__ == "__main__":
users = User(email="user1@gmail.com"), User(email="user2@gmail.com")
db.crea...
Check if pull needed in Git
... space-separated fields by the piped sed command, e.g. origin master.
This string is fed into git ls-remote which returns the head commit of the remote branch. This command will communicate with the remote repository. The piped cut command extracts just the first field (the commit hash), removing th...
Generating Guids in Ruby
...random UUID, so it is not guaranteed as unique. If you just want a random string that is probably unique it will be okay to use this. However, if you want something that is guaranteed to be unique you will need to use something that includes the MAC address, timestamp, and et cetera.
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MFC CString::Format()函数详解 - C/C++ - 清泛网 - 专注C/C++及内核技术
MFC CString::Format()函数详解我在编写程序时经常会使用CString::Format()来格式化字符串！但往往只是使用了Format很少一部分功能，比如整型转换成字符串！不过今天我想...我在编写程序时经常会使用CString::Format()来格式化字符串！但...