Deck 17: Cheat Sheet -> Direct Recall

pandas: select one column?

df['col']

pandas: select multiple columns?

df[['col1', 'col2']]

pandas: filter rows by condition?

df[df['col'] > value]

pandas: filter rows by multiple conditions?

df[(cond1) & (cond2)]

pandas: count categories in a column?

df['col'].value_counts()

pandas: quick statistics for a column?

df['col'].describe()

pandas: mean per group?

df.groupby('col').mean()

pandas: add a column?

df['new'] = values

pandas: sort rows?

df.sort_values('col')

pandas: select by label?

df.loc[row_label, col_name]

pandas: select by position?

df.iloc[row_int, col_int]

AnnData: inspect summary?

print(adata)

AnnData: get shape?

print(adata.shape) → (n_cells, n_genes)

AnnData: access a cell metadata column?

adata.obs['col']

AnnData: get a list of all gene names?

adata.var_names.tolist()

AnnData: subset cells by boolean mask?

adata[mask, :]

AnnData: subset specific genes?

adata[:, ['Hal', 'Vwf']]

AnnData: add cell metadata?

adata.obs['new'] = values

AnnData: access spatial coordinates?

adata.obsm['spatial']

AnnData: save to file?

adata.write_h5ad('out.h5ad')

AnnData: load from file?

ad.read_h5ad('file.h5ad')