Please assume the following dict is given
sources_targets =
{'front': {'source': [[0.021025050381526675, -0.39686011326197257, 3.328947963092819], [1.0601052368302668, -0.3938359761868055, 3.3247223740425893], [1.0543731204008824, -0.038184154352961984, 2.941639590795943], [0.017868184643970383, -0.0445863307249157, 2.9604912584916665]], 'target': [[-250.0, 0.0, 60.0], [-250.0, 0.0, -60.0], [-190.0, 0.0, -60.0], [-190.0, 0.0, 60.0]]}, 'left': {'source': [[-0.9522471062122733, -1.8444069007997075, 5.372044839796925], [-0.9665739520089994, -1.001259794819009, 5.0057689609608005], [0.9940538769534978, -1.851333804840362, 5.340677879647542], [0.9959517362506759, -1.0049420919111534, 4.942663843894899]], 'target': [[60.0, 0.0, 140.0], [60.0, 0.0, 80.0], [-60.0, 0.0, 140.0], [-60.0, 0.0, 80.0]]}, 'right': {'source': [[-0.8596841529333474, -3.0721166255322663, 4.182871479604773], [-0.8796404109762729, -2.117062488877432, 4.147040556143069], [1.0791152756424247, -2.0436646487085532, 4.08578012939533], [1.0951903113036177, -2.994375693306352, 4.124102127893507]], 'target': [[-60.0, 0.0, -140.0], [-60.0, 0.0, -80.0], [60.0, 0.0, -80.0], [60.0, 0.0, -140.0]]}, 'rear': {'source': [[0.08792816743383122, -0.5260295091566244, 3.0182522276468458], [0.9012540916522604, -0.5012267882763559, 3.0172622143554695], [0.8942115223224005, -0.15635208604951806, 2.6353057539009934], [0.08814313470840558, -0.18017837896764446, 2.6579174137231463]], 'target': [[250.0, 0.0, -40.0], [250.0, 0.0, 60.0], [190.0, 0.0, 60.0], [190.0, 0.0, -40.0]]}}
bundle_names = ['front', 'left', 'right', 'rear']
I want to get a list of all the sources and another list of all the targets.
Also, it needs to be done in a one-liner list comprehension.
My successful attempt is
sources3d = [st[1] for name in self._bundle_names for st in sources_targets[name].items() if st[0] == "source"]
targets3d = [st[1] for name in self._bundle_names for st in sources_targets[name].items() if st[0] == "target"]
with the correct output (for "sources" for example)
[[[0.021025050381526675, -0.39686011326197257, 3.328947963092819], [1.0601052368302668, -0.3938359761868055, 3.3247223740425893], [1.0543731204008824, -0.038184154352961984, 2.941639590795943], [0.017868184643970383, -0.0445863307249157, 2.9604912584916665]], [[-0.9522471062122733, -1.8444069007997075, 5.372044839796925], [-0.9665739520089994, -1.001259794819009, 5.0057689609608005], [0.9940538769534978, -1.851333804840362, 5.340677879647542], [0.9959517362506759, -1.0049420919111534, 4.942663843894899]], [[-0.8596841529333474, -3.0721166255322663, 4.182871479604773], [-0.8796404109762729, -2.117062488877432, 4.147040556143069], [1.0791152756424247, -2.0436646487085532, 4.08578012939533], [1.0951903113036177, -2.994375693306352, 4.124102127893507]], [[0.08792816743383122, -0.5260295091566244, 3.0182522276468458], [0.9012540916522604, -0.5012267882763559, 3.0172622143554695], [0.8942115223224005, -0.15635208604951806, 2.6353057539009934], [0.08814313470840558, -0.18017837896764446, 2.6579174137231463]]]
The way I accessed the inner dict using .items() and accessing the tuple by index seems cumbersome.
I would like to access some way with
[st["source"] for name in self._bundle_names for st in sources_targets[name]]
which doesn't work but would be much cleaner.
I am sure there is a way to do this correctly.
You iterate all the items and then pick the one (!) item that has the desired key. Instead, access the key directly.
This should work, yielding a result equal to your sources3d and targets3d:
sources3d = [sources_targets[name]["source"] for name in bundle_names]
targets3d = [sources_targets[name]["target"] for name in bundle_names]
If you need more than one item, you can basically do the same, but also iterate over the list of keys/items you would like to get:
>>> items = ["source", "target"]
>>> [sources_targets[name][item] for name in bundle_names for item in items]